here x intercept is -1, so coordinate would be (-1,0)
we use two points (2,7.5) and (-1,0) to find the slope
[tex] slope=\frac{y2-y1}{x2-x1} [/tex]
[tex] slope=\frac{0-7.5}{-1-2} [/tex]
slope=-7.5/-3 = 2.5
now let us use slope m =2.5 and point (-1,0) to get the y intercept
y=mx+b
0=2.5(-1)+b
b=2.5
plugging value of m and b in slope intercept form to get the equation
y=2.5x+2.5