The x-intercept is the value of x when y is equal to zero or the point on x-axis at which a straight line intersects in xy-plane. Hence:
Y = -4x + 8 (your statement)
0 = -4x + 8 (set y to 0)
0 - 8 = -4x + 8 - 8 (subtract 8 from both sides)
-8 = -4x (collect terms)
-8/-4 = -4x/-4 (divide both sides by -4)
2 = x
Y = -4x + 8 (your statement)
0 = -4x + 8 (set y to 0)
0 - 8 = -4x + 8 - 8 (subtract 8 from both sides)
-8 = -4x (collect terms)
-8/-4 = -4x/-4 (divide both sides by -4)
2 = x