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Solve the system by substitution. x−2y=5 −7x+4y=−45 ​

User Jabda
by
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1 Answer

2 votes

Answer:

x = 7

y = 1

Explanation:

1) x−2y = 5

2) −7x+4y = −45

Solving by substitution means we need to get rid of one of the variable.

We can do that as follows:

Multiply

the first equation by 2.

2x - 4y = 10

Add both equations up.

2x - 4y - 7x + 4y = 10 - 45

Add/subtract

like terms

.

-5x = -35

It can be written in

positive form

since both sides are negative.

5x = 35

Divide

both sides by 5.

x = 7

To find the value of y, replace x with 7 in the first equation:

7 - 2y = 5

Subtract

7 from both sides.

-2y = -2

Again, it can be written in positive form.

2y = 2

Divide both sides by 2.

y = 1

User Hari Narayanan
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8.0k points