Question

Which ordered pair would be the solution to this system of equations?

3x-4y=20
y=-3x+10

A(4,2) B(4,-2) C(-4,-2) D-4,22)

Answer 1

Check if the first pair is a solution of the system:

A(4,2) 

$$\begin{alignedat}{2} 3*4- 4*2=4 {=}\mathllap{/\,} 20 \\ 2{=}\mathllap{/\,}-3*4 +10=-2 \end{alignedat}$$

A(4,2) is not the solution to this system of equations

B(4,-2)

$$\begin{alignedat}{2} 3*4- 4*(-2)=20 \\ -2=-3*4 +10 \end{alignedat}$$

B(4,-2) is the solution to this system of equations

C(-4,-2)

$$\begin{alignedat}{2} 3*(-4)- 4*(-2)=-4 {=}\mathllap{/\,} 20 \\ -2{=}\mathllap{/\,}-3*(-4) +10=22 \end{alignedat}$$

C(-4,-2) is not the solution to this system of equations

D(-4,22)

$$\begin{alignedat}{2} 3*(-4)- 4*22=-100 {=}\mathllap{/\,} 20 \\ 22{=}\mathllap{/\,}-3*(-4) +10=22 \end{alignedat}$$

D(-4,22) is not the solution to this system of equations

ANSWER:

B(4,-2) is the solution to this system of equations