Carlos M. answered 04/04/13
Multiple Grads+Experience for Effective Math/Italian/Spanish Tutoring
Solution: A = 2 Please read the following step by step solution.
STEP 1: Read, understand the situation within, identify and pull out important information.
- y = (2/3)x - 6 it's in a slope form equation y=mx+b, where m(slope)=2/3; b(y-intercept)=-6
- The standard form equation leads to the slope form equation just by isolating "y" and by doing opposite operations.
- To transform a "slope form" into a "standard form", we just do the inverse process: the variables x, y, must be in the same side of the equation.
STEP 2: Translate keywords to their mathematical symbols:
- Standard form equation: Ax + By = C, where A is a positive integer, B and C integer numbers
- A = ? ; B = ? ; C = ?
STEP 3: Set up and solve the equation or problem:
y = (2/3)x - 6 Get rid of the variable x (with its coefficient) on the right side
-(2/3)x -(2/3)x
-(2/3)x + y = -6 As "A" must be positive integer, get first rid of the denominator of the fraction coefficient of "x", by multiplying the whole equation by "3"
3 * ((-2/3) (x) + y = -6) Apply the distributive property of multiplication
(3/1)*(-2/3) (x) + 3y = 3*(-6)
(3*-2)/(1*3) (x) + 3y = -18 Simplify
-2x + 3y = -18 Now get rid of the negative sign of "x" by multiplying the whole equation by -1
(-1) (-2x + 3y = -18) Apply the distributive property of multiplication
2x - 3y = 18 There you have the equation in standard form! A = 2
STEP 4: Check the solution:
Transform the standard form equation solution into a slope intercept form. We must get the original equation given in slope intercept form!
2x - 3y = 18 Isolate "y" by first getting rid of 2x in the left side of the equation
-2x -2x
-3y = -2x + 18 Get rid of the coefficient -3, by dividing the whole equation by -3
(-1/3) (-3y = -2x + 18) Applying the distributive property of multiplication
(3/3)y = (2/3)x + (-1/3) (18) Simplifying
y = (2/3)x -6 We got the same original slope intercept form equation!
STEP 5: Curiosities
- Having the equation in "standard form" it's really easy to get the y-intercept point (0,y) and the x-intercept point (x,0).
y-intercept: 2(0)-3y=18; -3y=18; (-3/-3)y=(18)/(-3); y=-6;
y-intercept point (0, -6)
x-intercept: 2x-3(0)=18; 2x=18; (2/2)x=(18)/(2); x=9;
x-intercept point (9, 0)
- Graphing the equation in standard form: find the y-intercept point and x-intercept point, as we already did it. Plot them in a Cartesian plane and draw a line through both intercept points. And voila' you got it!