Question

A system of equations is shown below:Equation A: 3c = d − 8Equation B: c = 4d + 8Which of the following steps should be performed to eliminate variable d first?Multiply equation A by −4.Multiply equation B by 3.Multiply equation A by 3.Multiply equation B by 4.

Answer 1

We have the following: system of equations:

A: 3c=d-8

B: c=4d+8

To eliminate variable d first, if we want to use elimination method, we need to have variable d in both equations with the same coefficient but with different signs.

As in equation B, the coefficient of d is 4, then we need to have in equation A a coefficient of -4 for variable d.

Then the answer is we need to multiply equation A by -4.