Find a number minus 9 and multiply it by 4. The product is 64

Find a number minus 9 and multiply it by 4. The product is 64

Let this number be X
（x-9）*4=64
x-9=64÷4
x-9=16
x=9+16
x=25

A number minus 2.4 times 3, the difference is 15, what is the number? How is the equation listed?

Let this number be X
x-2.4×3=15
x-7.2=15
x=15+7.2
x=22.2

Solve the following equation: (four fifths X-10) divided by (X-8) = five fifths X

Multiply both sides by 7 (X-8)
7 times (four fifths X-10) = 5 times (X-8)
Twenty eight fifths - 70 = 5x-40
Twenty eight fifths - 5x = - 40 + 70
Three fifths x = 30
x=50
Test: bringing x = 50 into 7 (X-8) is not equal to 0
So x = 50 is the solution of the original fractional equation