So why did you post the same thing twice in 25 minutes?????
That's a no-no on bulletin boards.
This is a physics problem.
But if you want to solve it like it was a math problem - okay.
1st you can find the x-axis of symmetry. x= -b/2aThen you can find ...

For a polynomial of form Ax^2 + Bx + C = 0
A tells the end behavior. Negative says it opens down, the end behavior is down on both left and right.
The axis of symmetry is given by x = -b/2a
Find -b/2a, that is the ex value for the vertex.
Plug that value into...

If you look at the sides you can see that they are in a ratio of 3,4,5.
This is a 3,4,5 triangle - one of the special triangles that never gets put in the book with the 45-45-90 and 30-60-90.
So you can see this is a right triangle with the long (10) side as the hypotenuse.
Draw a picture...

Evidence is at the bottom after explanation.
The green color of leaves is from the chlorophyll in the leaves.
BUT - chlorophyll is Not Green. There are two colors of
chlorophyll; red and blue.
The mixture of these two colors being absorbed makes the leaves 'look'...

For f(6) it means you plug 6 into the equation for x and evaluate it.
Like this:
f(x) = 8x - 2
= 8(6) - 2
= 48 - 2 = 46
Do the rest by putting in 1.5, 0, a,...

7x + 9y - 7 = -9
move all but 'y' to the right side
9y = -7x +7 - 9
= -7x -2
divide by 9
y = -7x/9 -2/9
= (-7/9)x -2/9
so compare to y = mx +b
and you can find the slope and interc...

d/dx(x^(1/x))
Express x^(1/x) as a power of e
x^(1/x) = e^(log(x^(1/x))) = e^((log(x))/x)
= d/dx(e^((log(x))/x))
Using the chain rule
d/dx(e^((log(x))/x)) = ( de^u)/( du) ( du)/( dx)
...

d/dx (log(4) x e^x)
Factor out constants:
= log(4) (d/dx(e^x x))
Use the product rule,
d/dx(u v) = v ( du)/( dx) +
u ( dv)/( dx),
where u = e^x and
v = x:
=...

You have a quadratic in the form of:
y = (x-h)^2 + k
1) The vertex is (h,k) or (2,-1)
2) The axis of symmetry is x=h (or x=2)
3) The a=1/2 widens the parabola and is + so the graph opens up
The h = +2 shifts the parabola 2 to the right of the y axis
The...

Write two equations.
the difference of the two numbers is 17
X - Y = 17
the larger is twice the smaller decreased by 13
X = 2 ·Y - 13
Now solve the simultaneous equations by any method, substitution or by elimination.

But they are not in alphabetical order.
CAT - 60
BEAR = 180
sorry but Bear should come before Cat, it is ABC not ACB.

The bank is 1/3 full - that is the same as 2/6 full.
When she added 440 pennies if went from 2/6 full to 5/6 full.
5/6 - 2/6 = 3/6 increase for the 440 pennies.
There are 2 ways to think of it from here:
1) 440 pennies was 3/6 of the bank so dividing by 3
...

How many dice??
If you roll 1 die there are 5 possibilities.
If you roll 2 there are 5x5 posibilities
Roll 3 and there are 5x5x5 possibilities.

For a parabola in the form
y = A(x-h)2 + k the vertex is (h,k)SO
1) Rewrite the equation in that form.
OR
Using the x axis of symmetry is -(b/2a)
find x then substitute that into the equation
to get the y value.
x = -(b/2a)...

The tax is 9% of $65.40
The tip is 20% of $65.40 - a very generous tip btw.
Tax = 0.09(65.40) = ?
Tip = 0.20(65.40) = ?
For the total add up 65.40 plus the tax plus the tip.
I am going to assume you can do the arithmetic on your own.
This...

If this is a thermal chemistry or physics problem there are some things you might be expected to know.
If this is a mathematics (pre-calc) problem then you need to know if the change in temperatures is a linear relationship or not, and if not what king of relationship.
In either...

You gave the method to the solution in your question.
Solve by substituting
y=3x+4 INTO
7x+2y=21
7x+2y=21
becomes
7x+2(3x+4)=21
distribute
7x+6x+8=21
now solve for x

This problem (a physics problem) requires a little more than just being able to solve a simple math formula.
You need to understand what is going on well enough see that if one is going X speed and the other is going Y speed then they are traveling towards each other at a speed of
X+Y...

Asking the same question twice in 2 minutes only ticks off those of us who are here giving free advice.

x + 0.15 x = $2
can be thought of as
1(x) + (0.15)x = $2
so you can change the left side into
1(x) + (0.15)x
=
(1 + 0.15)x
=
(1.15) x
giving
(1.15) x = $2
now just solve this for x