Question

9. Solve the system of equations using substitution.
y = 2x - 10
y = 4x - 8​

Answer 1

Since they’re both in standard form and they both say that y is equal to something, you just have to set them up with one another
2x-10=4x-8
Subtract 2x
-10=2x-8
Add 8
-2=2x
Divide by 2
-1=x
x=-1
Check it by inserting it
2(-1)-10=4(-1)-8
-2-10=-4-8
-12=-12
So x=-1 is the answer

Answer 2

-1

Explanation:

Move all terms containing x

to the left side of the equation.

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Subtract 4x from both sides of the equation.

2 x−10−4x= −8 y=4x−8

Subtract 4 x from 2 x − 2 x− 10= − 8 y = 4 x − 8

Move all terms not containing x to the right side of the equation.

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− 2 x = 2 y = 4 x − 8

Divide each term by − 2 and simplify.

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Divide each term in − 2 x= 2 by − 2 .

− 2 x − 2 = 2 − 2 y = 4 x − 8

Simplify the left side of the equation by cancelling the common factors.

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Reduce the expression by cancelling the common factors.

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− ( − 1 ⋅ x ) = 2 2 y = 4 x − 8

Rewrite

− 1 ⋅ x as - x . x = 2 − 2 y = 4 x − 8

Divide 2 by − 2 .

x = − 1 y = 4 x − 8

Replace all occurrences of x with the solution found by solving the last equation for x . In this case, the value substituted is − 1 . x= − 1 y = 4 ( − 1 ) − 8

Simplify 4 ( − 1 ) − 8 .

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Multiply 4 by − 1 .

x = − 1 y = − 4 − 8

Subtract 8 from - 4 .

x = − 1 y = − 12

The solution to the system of equations can be represented as a point.

( − 1 , − 12 )

The result can be shown in multiple forms.

Point Form: ( − 1 , − 12 )

Equation Form: x =− 1 ,y = − 12