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# need a little help (answer)

You can add/subtract a multiple of one equation to/from another.  This will let you eliminate a variable.   (1) x + 4y = 8 (2) 5x + 6y = 12   For this problem, we can multiply the first equation by 5: (1) 5*(x+4y) = 5 * 8 (1) 5x + 20y = 40   Now both equations...

# what is the charge in coulombs of the nucleus of a copper atom (answer)

Look at the atomic number of the element copper (Cu).  That is the number of protons in the nucleus (as well as the number of electrons).  Copper is 29.   The elementary charge per proton (or electron) is 1.602x10^-19 coulomb.  This is a positive charge for protons and negative for electrons...

It looks like two brothers each have an account.  One is adding money monthly and the other is making withdrawals.  If that is the case, you left an "m" out of the equation.  Also, is the starting value of one account really a negative number?   First I'll assume that my scenario is correct,...

To answer the question you asked, the equation is 5.5x+32=57   If you want to know what x is: 5.5x = 57-32 =25 x = 25/5.5 x = 4.5454...

# Rewrite the function y=3px in y=mx+b form (answer)

Susannah,   Yes, the function is linear.  How can you tell?  It's because the term with x in it is just x.  If it had a term with x2 or x3, it would curve instead of being a straight line (linear).   The equation is actually already in slope intercept form! Besides the unknown...

Average speed is just the total distance traveled divided by the total time.   You already have the total time.  It's 100 + 100 = 200 seconds.   Calculate the two distances, add them together, then divide by 200:   D1 = 100 * 5 = 500 m D2 = 100 * 1 = 100 m   Total...

# In the equation 3x+2y=9, if x increases by 2 then y does what? (answer)

Another way to get the answer is to put the equation in slope-intercept form: y = mx + b   3x+2y=9   2y = -3x + 9   y = (-3/2)x + 9/2   The slope (-3/2) tells you how much y changes for each unit change in x.   If x increases 2 units, y changes by mx = (-3/2)...

# how do you work this problem?a/-9=2 (answer)

Don't let the minus sign confuse you.   Just multiply both sides of the equation by -9:   I'll include extra parentheses for more clarity.   a / (-9) = 2   (a) * (-9) / (-9) = 2 * (-9)   a * 1 = -18   a = -18

# Is there a relationship between the sign (positive or negative) of the slope of a line and the angle the line makes with the x-axis? (answer)

Mathematically, the answer is definitely "yes"!   A line with positive slope rises from left to right, negative slope falls from left to right.   When they intersect the x-axis and you measure the angle of the intercept from left to right, two lines with the same magnitude slope...

# Micheal wants his \$3,200 to grow to \$4,500 in 3 years. He has a saving account paying simple interest on savings. (answer)

Barbara,   Simple interest uses the formula: I = prt where p = the initial principal, r = the interest rate per unit time t = time in the units used to express the interest rate. Your time unit is "year", and the interest rate is annual interest (per year).   Simple...

Tami,   12=4(b-2) Expand the right side using the distributive rule: 12=4b - 4*2 12=4b - 8 Add 8 to both sides: 12+8 = 4b - 8 + 8 20 = 4b Divide both sides by 4: 20/4 = 4b / 4 5 = b   All you need to know is the distributive rule of multiplication: a...

I can't be sure what form the answer is expected to have. You could divide the numerator and denominator by -4x2: -20x6 - 24x4 - 12x2        5x4 + 6x2 + 3 -----------------------  =   ---------------          -4x4                           x2 Or you could do this:  -20x6...

# how do I evaluate natural log functions (answer)

This question is testing your understanding of what a natural logarithm is. There is a special number called "e".  There is some power that you could raise e to that will give you the result of 5.  As a formula, that would look like this: ex = 5. That x is defined as the natural logarithm...

# Describe the magnitude and direction of the vector or vectors in the following situation: an airplane flying northwest at 175 knots (answer)

The difference between a scalar and a vector is that one is just a number, while the other represents a number pointed in some direction. Speed is a scalar.  It's just a magnitude and doesn't specify any direction. Velocity is a vector.  Its magnitude is the speed and its direction is northwest...

# Two trains leaving the station at different times... (answer)

The trick with word problems is to pick them apart to see what you know, then build equations that you can solve.  It takes some practice. In this problem, we know that one train starts two hours before the other one and travels at a known rate. Let's calculate how far it goes in those two hours: d...

# For a certain installment loan, the monthly payment M is given by M = Pr(1 + r)t (1 + r)t - 1 (answer)

The formula as written has all of the correct symbols, but it's missing some important stuff. M = Pr(1+r)^t / [(1+r)^t - 1] looks like the equation you are using. First, are you sure that the MONTHLY interest rate is 0.05?  That's 60% annual interest! Try r = 0.05 / 12 to convert a 5%...

# You have just received word that your original investment of \$650 has increased in value by 17%. What is the value of your investment today? (answer)

For your introduction to this type of problem you should solve it this way so you understand how it works: Since you started with \$650 and it went up by 17%, you can calculate what 17% of \$650 is, then add that to the starting amount. 17% is the same as 0.17, so 17% of \$650 is: \$650...

# how do I convert 11.76% to a fraction and simplify the result (answer)

If you're still wondering how to come up with    1176  10000 11.76% = 0.1176 Divide it by 1.  You don't need to write this step down.  It just shows you how it works.  0.1176 = 0.1176                    1 Multiply both the numerator and denominator by 10 until both numbers...

# find the y intercept (answer)

Equation of a line: y = mx + b m = slope ("gradient") b = y-intercept You know a pair of values for x and y, so plug them and the slope into the equation and solve for b: Point (x, y) = (-3, 3) m = 3 y =    mx    + b 3 = (3)(-3) + b     y=3, m=3, x=-3 3 = -9 + b 3+9...

# I need help to factor the trimonial of 2 problems. (answer)

ax2 + bx + c When the first coefficient is not 1, it's easiest to use what's called AC factoring. 1. Multiply a by c.   ac = (6 * 2) = 12 2. Find two factors of ac that add up to b.     You'll have to pay attention to the signs.  If ac is positive, both factors will have the same...