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2 years ago

Solve the system by substitution. 3x + y = 20 -7y=x Please help

Mathematics

1 answer:

alisha [4.7K]2 years ago

8 0

9514 1404 393

Answer:

(x, y) = (7, -1)

Step-by-step explanation:

The expression for x makes it easy to use that for substitution.

3(-7y) +y = 20

-20y = 20 . . . . . collect terms

y = -1 . . . . . . . . . divide by -20

-7(-1) = x = 7 . . . use y in the second equation to find x

The solution is (x, y) = (7, -1).

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