Question

Solve the system of equations using a matrix. x+3y=11 4x-y=31

Answer 1

`\sf \: x=8 and y=1`

Explanation:

Let's solve your system by elimination.

x+3y=11;4x−y=31

Multiply the first equation by -4,and multiply the second equation by 1.

−4(x+3y=11)

1(4x−y=31)

Becomes:

−4x−12y=−44

4x−y=31

Add these equations to eliminate x:

−13y=−13

Then solve−13y=−13for y:

−13y=−13

−13y/−13=−13/−13

(Divide both sides by -13)

y=1

Now that we've found y let's plug it back in to solve for x.

Write down an original equation:

x+3y=11

Substitute1foryinx+3y=11:

x+(3)(1)=11

x+3=11(Simplify both sides of the equation)

x+3+−3=11+−3(Add -3 to both sides)

x=8