Question

2. What values of a and y make the following system of linear equations true?

-7x +6y=1
-4x + 3y = 4

A. x = 7, y=8
B. x = -7, y=-8
C. x = -1, y=-4
D. x=1, y = 4

Answer 1

B. x = -7, y = -8

Explanation:

Equation 1 : -7x + 6y = 1

Equation 2 : -4x + 3y = 4

Multiply Equation 2 by 2.

• 2(-4x + 3y) = 4(2)
• Equation 3 : -8x + 6y = 8

Subtract Equation 3 from Equation 1.

• -7x + 6y - (-8x + 6y) = 1 - 8
• -7x + 8x + 6y - 6y = -7
• x = -7

Substitute x in Equation 1.

• -7(-7) + 6y = 1
• 6y = -48
• y = -8

Solution

• x = -7, y = -8
• Option B