Question

Solve the system of equations - 8x - 5y = -13 and - 4x – 5y = 11 by
combining the equations.

Answer 1

(6,-7)

Explanation:

subtract them:

-8x - 5y = -13

-4x - 5y = 11

you get

-4x = -24

so x = 6

plug x into the second equation:

-24 - 5y = 11

-5y = 35

y = -7

so your solution is (6,-7).

Answer 2

Your solution is (6, -7).

Explanation:

Combining the equations is also known as substitution. This is done when you substitute one variable into another equation.

-8x - 5y = -13

-4x - 5y = 11

Let's change the second equation into one with one variable on each side.

-5y = 4x + 11

y = -4/5x - 11/5

Now, plug this into your first equation.

-8x - 5(-4/5x - 11/5) = -13

Distribute the -5 sign.

-8x + 4x + 11 = -13

Combine the like terms.

-4x + 11 = -13

-4x = -24

Isolate x by dividing both sides by -4.

x = -24/-4

x = 6

Now plug this back into either equation.

y = -4/5(6) - 11/5

Multiply.

y = -24/5 - 11/5

Subtract.

y = -35/5

Simplify.

y = -7

Your solution is (6, -7).

Check this by plugging in these values into the equation you have not checked yet.

-8(6) - 5(-7) = -13

-48 + 35 = -13

-13 = -13

Your solution is correct.

Hope this helps!