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.

You did not include the choices. However, I answered one that just included them. I've included the possible answers below and then the correct answers. 

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.

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.