X - intercepts are also known as zeros. To solve this simply take each factor of the polynomial and set it equal to zero. Solve for x then you'll have your x - value of the x intercept.
x - 1 = 0
x - 1 +1 = 0 + 1
x = 1
x - 4 = 0
x - 4 + 4 =0 +4
x = 4
x + 7 = 0
x + 7 - 7 = 0 - 7
x = -7
^^^All the above are the x values of the x - intercepts
