What are the steps for substitution(word problems)? and !

Find the equation of the line that goes through the points (4, –1) and (2, –5). use slope formula,equation,to find the slope of a line that passes through the points. m = use slope-intercept form, y = mx + b, to find the y-intercept (b) of the line. b = write the equation in slope-intercept form, y = mx + b.

1-for what value of x is line a parallel to line b 2-for what value of x is line a parallel to line b

Find the solution of this system of equation -7x+y=-20 9x-3y=36