Question

Equation 1:Ax+By=C Equation 2:Dx+Ey=F A, B, C, D, E, and F are non-zero real numbers. Which of the following could replace equation 1 and still have the same solution? Select all that apply.
A. A multiple of Equation 1.
B. The sum of Equation 1 and Equation 2
C. An equation that replaces only the coefficient of x with the sum of the coefficients of x in Equation 1 and Equation 2.
D. An equation that replaces only the coefficient of y with the sum of the coefficients of y in Equation 1 and Equation 2.
E. The sum of a multiple of Equation 1 and Equation 2.

Answer 1

A, B and E.

Adding and multiplying the terms allow them to keep working. However, you must make sure that each variable is changed each time. Not just one as in C and D.