Question

Activity B (continued from previous page)

3. Consider the system of equations y = -x + 3 and y = 4x+8.
A. Use the substitution method to find the solution
of this system. Show your work to the right.
B. What is the solution of this system? CI

Answer 1

A. (see Step-by-step explanation)

B. (-1, 4)

Explanation:

Since both functions are equal to y, we can set them equal to each other.

-x + 3 = 4x + 8

Add the x to both sides (because it is negative on the left) and subtract the 8 from both sides (because it is positive on the right and we need to isolate the variable).

-5 = 5x

Divide both sides by 5 (because it is being multiplied to the x) to isolate x.

x = -1

Next, to solve for y, we can plug in -1 for x in either equation from the beginning.

y = -(-1) + 3

y = 1 + 3

y = 4