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Solve this by substitution method

0 votes
please help solve?

x + 8y = -5

4x - 5y = -20
asked Nov 2, 2013 in ALGEBRA 1 by payton Apprentice

1 Answer

0 votes

The equations are

x + 8y = -5 --------- (1)

4x - 5y = -20 -------- (2)

Solve the first equation for x since the coefficient of x is 1.

x +8y = -5

Subtract 8y from each side.

x = -8y - 5

Substitute x = -8y - 5 in 4x - 5y = -20

4 * (-8y - 5) - 5y = -20

-32y - 20 - 5y = -20

-37y -20 = -20

Add 20 to each side.

-37y = 0

y = 0

Substitute y = 0 in x = -8y - 5.

x = -8 * 0 - 5

x = -5

(x, y) = (-5, 0).

answered Nov 2, 2013 by steve Scholar

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