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Solve by Substitution 7x+2y=-19 , -x+2y=21

User Luming
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Final answer:

To solve the equations 7x+2y=-19 and -x+2y=21 by substitution, we first solved the second equation for x, and then substituted this expression into the first equation to find y. After finding y, we substituted it back into the expression for x to find its value. The solution is x = -5 and y = 8.

Step-by-step explanation:

To solve the system of equations 7x+2y=-19 and -x+2y=21 by substitution, we start by solving one of the equations for one variable and then substituting that expression into the other equation. Let's solve the second equation for x:

-x + 2y = 21

-x = 21 - 2y

x = -21 + 2y

Now, substitute x in the first equation with the expression we found:

7(-21 + 2y) + 2y = -19

-147 + 14y + 2y = -19

16y = 128

y = 8

With the value of y found, substitute it back into the expression for x:

x = -21 + 2(8)

x = -21 + 16

x = -5

Therefore, the solution to the system of equations is x = -5 and y = 8.

User Akhil Latta
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