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19 votes
19 votes
Figure out by using substitution

5x + 2 y = 7
4x + y = 8​

User Luis Henrique
by
2.9k points

1 Answer

18 votes
18 votes

Answer:

(3, - 4 )

Explanation:

Given the 2 equations

5x + 2y = 7 → (1)

4x + y = 8 → (2)

Rearrange (2) expressing y in terms of x by subtracting 4x from both sides

y = 8 - 4x → (3)

Substitute y = 8 - 4x into (1)

5x + 2(8 - 4x) = 7 ← distribute and simplify left side

5x + 16 - 8x = 7

16 - 3x = 7 ( subtract 16 from both sides )

- 3x = - 9 ( divide both sides by - 3 )

x = 3

Substitute x = 3 into (3) for corresponding value of y

y = 8 - 4(3) = 8 - 12 = - 4

solution is (3, - 4 )

User Noisebleed
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3.2k points