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5 votes
3x-2y=10
9x+4y=-50
solve by subtitution step by step

User Kyle West
by
3.7k points

1 Answer

5 votes

Answer:

(- 2, - 8 )

Explanation:

3x - 2y = 10 ( add 2y to both sides )

3x = 2y + 10 โ†’ (1)

9x + 4y = - 50 , or

3(3x) + 4y = - 50 โ†’ (2)

substitute 3x = 2y + 10 into (2)

3(2y + 10) + 4y = - 50

6y + 30 + 4y = - 50

10y + 30 = - 50 ( subtract 30 from both sides )

10y = - 80 ( divide both sides by 10 )

y = - 8

substitute y = - 8 into either of the 2 equations and solve for x

substituting into (1)

3x = 2(- 8) + 10 = - 16 + 10 = - 6 ( divide both sides by 3 )

x = - 2

solution is (- 2, - 8 )

User Feyzi Bagirov
by
3.1k points