Question

1. At which ordered pair on a graph will the following system of a linear equations intersect?

-5x + 5y = -10
-3x + 2y = 3

A. (7,9)
B. (10,-3)
C. (-10,3)
D. (-7, -9)

Answer 1

D. (-7, -9)

Explanation:

Equation 1 : -5x + 5y = -10

Equation 2 : -3x + 2y = 3

Multiply Equation 1 by 2 and Equation 2 by 5.

• -10x + 10y = -20 [Equation 3]
• -15x + 10y = 15 [Equation 4]

Subtract Equation 4 from Equation 3.

• -10x + 10y + 15x - 10y = -20 - 15
• 5x = -35
• x = -7

• -3(-7) + 2y = 3
• 2y = -18
• y = -9

Solution

• (-7, -9)