Solve by Substitution 2x-8y=40 , -7x+9y=-7

Problem

{[2*x−8*y=40],[−7*x+9*y=−7])

Solution

1. Solve the first equation for x by isolating the term.

2*x=8*y+40

x=4*y+20

2. Substitute the expression for x into the second equation.

−7*(4*y+20)+9*y=−7

3. Distribute the −7 and combine the like terms to solve for y

−28*y−140+9*y=−7

−19*y−140=−7

−19*y=133

y=−7

4. Substitute the value of y back into the expression for x

x=4*(−7)+20

x=−28+20

x=−8

Final Answer

(x,y)=(−8,−7)

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