here is the picture as you see the line crosses Y-axis on point 5 so the intercept is +5 nowyou can put (2,-1)as x and y to find the slope [tex] - 1 = 2a + 5 \\ - 1 - 5 = 2a \\ - 6 = 2a \\ a = \frac{ - 6}{2} = - 3[/tex] the slope is -3 so the correct equation will be y=-3x+5
