Add 15to a number then multiply the result by 3 the answer is the same as subtracting 4 from the number and multiplying the result by 5 find the number

2 answers

3(x+15) = 5(x-4)
3x + 45 = 5x - 20
-2x = -65
x = 32.5 <----- the number

check:
add 15 to 32.5 ---> 47.5
multiply 47.5 by 3 ---> 142.5

subtract 4 from 32.5 --> 28.5
multiply by 5 --> 142.5

my answer is correct.
321_2,