Question

How do I solve this using substitution? Please write down the steps too.

6x+5y=-16
y=7x+5

Answer 1

x = -1

y = -2

( -1, -2 )

Explanation:

6x + 5y = -16

They gave us what "y" is and its....

y = 7x + 5

We substitute the "y" in the equation with this "y = 7x + 5

"

6x + 5y = -16

6x + 5(7x + 5) = -16

Now we need to use the distributive property (multiply what is in the parenthesis by "5")

6x + 5 * 7x + 5 * 5 = -16

6x + 35x + 25 = -16

Combine Like Terms ( 6x and 35x)

41x + 35 = -16

Subtract 25 on both sides

41x + 35 - 25 = -16 - 25

41x = -41

Divide by 41 on both sides to isolate the variable

41x/41 = -41/41

x = -1

Now that we have what "x" is (-1) we can use that to find out what "y" is.

y = 7x + 5

Substitute the x with -1

y = 7x + 5

y = 7(-1) + 5

y = -7 + 5

y = -2

x = -1

y = -2

( x, y )

( -1, -2 )

Hope this helped!

Have a supercalifragilisticexpialidocious day!

Answer 2

Answer: x = -1 and y = -2

Explanation:

You are given two expressions that have a relationship. There are two ways to solve this problem, but I will be going over the easy way. I'm assuming you know how to solve for one variable such as x? Well we can put the y varaible from the first equation in terms of x, from the second equation. Ill show you what I mean:

6x + 5(7x + 5) = -16

I replaced y in the first one in terms of x, so that we can solve just for x.

6x + 35x + 25 = -16

41x +25 = -16

41x = -41

x = -1

Now simply find y by plugging the now known x value into either equation

y = 7(-1) + 5

y = -2