Straight line: y = mx + c m is the slope of the graph and c is the y-intercept In this case, m = 5 as stated in the question, so... y = 5x + c By substituting the given co-ordinates (-2,-1) into this equation, we can find c -1 = 5(-2) + c -1 = -10 + c -1 + 10 = -10 + c + 10 (Add 10 to both sides) 9 = c c = 9 Put c = 9 into the equation: y = 5x + 9
