Solve using elimination.

7x + 4y = - 3

-7x + 5y = 12

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Questions

(x, y) → ( - 1, 1)

given the 2 equations

7x + 4y = - 3 → (1)

- 7x + 5y = 12 → (2)

add (1) and (2) term by term to eliminate x

(7x - 7x) + (4y + 5y) = ( - 3 + 12)

9y = 9 (divide both sides by 9)

y = 1

substitute y = 1 into either (1) or (2) and solve for x

(1) : 7x + 4 = - 3 (subtract 4 from both sides)

7x = - 7 (divide both sides by 7)

x = - 1

solution is (x, y) → ( - 1, 1)

Just adding the 2 equations eliminates the terms in x (7x + - 7x = 0) giving:-

0 + 9y = 9

y = 1

Plug this into the first equation:-

7x + 4 (1) = - 3

7x = - 7

x = - 1

Answer x = - 1 and y = 1.