When solving the following system of equations by substitution what would be a correct first step?

{x=y- 7 3x + 15y =- 1

A. 3x + 15 (y - 7) = - 1
B. 3(y – 7) + 15y = - 1
C. 3x + 15y (y - 7) = -1
D. 3x(y – 7) + 15y = -1

dude   i don't even know. i've been trying for hours.

step-by-step explanation:

solve systems of equations by graphing. a system of linear equations contains two or more equations e.g. y=0.5x+2 and y=x-2. the solution of such a system is the ordered pair that is a solution to both equations. to solve a system of linear equations graphically we graph both equations in the same coordinate system

the answer is:

mean: 6

mad: 2.14