Which of the following situations may cause someone to use substitution, in order to solve a system of equations?

a. an exact solution is not needed.
b. one of the equations may easily be solved for a variable.
c. an exact solution is needed.
d. both of the equations are solved for one variable.

If you want to substitute, you need to solve an equation for a variable.  I ONLY use this method if I can easily solve one equation for a variable, and then it is a maybe.  For this case use B

Abit confused about what you mean, but i think you might be referring to slope intercept form: y = mx + bin that case b, or the y intercept is already given.(0,-1)find the slope by using the formulay2 - y1/x2 - x1the final slope will be 4/2, equivalent to 2.now your equation should look like thisy = 4/2x -1sorry if this didn’t you out!