F (x) = 4x ⇒ y = 4x
↓
x = 4y Divide by 4 on both sides
↓
x / 4 = y ⇒ Inverse function = x / 4
Find common denominators. 10 is the common denominator. Multiply 2 to numerator and denominator of -3/5
(-3/5)(2/2) = -6/10
x + 1/10 = -6/10
Isolate the x. Subtract 1/10 from both sides
x + 1/10 (-1/10) = -6/10 (-1/10)
x = -6/10 - 1/10
x = -7/10
-7/10 is your answer for x
hope this helps
#4)
cross multiply
2(8x+10) = 4 * 5x
16x + 20 = 20x
4x = 20
x = 5