Question

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

Answer 1

please help me i don't understand

Answer 2

add 15 to a number ... x+15
multiply the result by 3 ... 3(x+15)
that is the same as

subtracting 4 from the number ... x-4
multiply the result by 5 ... 5(x-4)

so now just solve
3(x+15) = 5(x-4)
3x+45 = 5x - 20
2x = 65
x = 65/2 = 32 1/2

and yes, that <u>is</u> the answer.
But, as always, you should check it to be sure it works as required.

Answer 3

thanks