Question

Solve the system of linear equations using elimination.10x + 7y = 128x + 7y = 18A)(3, 6)B)(3, −6)C)(−3, 6)D)(−3, −6)

Answer 1

So we subtract equation (2) from equation (1) to eliminate y

10x+7y=12...............(1)

-

8x+7y=18.................(2)

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2x + 0 = -6

2x = -6

2x/2 =-6/2

x = -3

From equation (1) substituting for x yields

10(-3) +7y =12

-30 +7y = 12

7y = 12+30

7y = 42

7y/7 = 42/7

y= 6

(-3,6)

Option C