Question

Urgent please help quick!!!

Solve the system of linear equations by substitution

5x+5y=-10
3x - 7y = 4​

Answer 1

`x=-1\\y=-1`

Explanation:

`5x+5y=-10\\3x-7y=4`

Let's solve the first equation for either x or y. I'll do it for x.

`5x+5y=-10`

Begin by subtracting 5y.

`5x=-5y-10`

Now divide by 5.

`x=(-5y)/(5)-(10)/(5)`

Simplify:

`x=-y-2`

Now substitute x in the second equation for this value.

`3x-7y=4\\3(-y-2)-7y=4`

Distribute;

`-3y-6-7y=4`

Add 6

`-3y-7y=4+6`

Combine like terms;

`-10y=10`

Divide by -10.

`y=(10)/(-10)\\ y=-1`

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Take this value of y and replace it in the first equation to find the value of x.

`5x+5y=-10\\5x+5(-1)=-10\\5x-5=-10\\5x=-10+5\\5x=-5\\x=(-5)/(5)\\ x=-1`