(3 + 2(8 + 5 • 2 ÷ 4) – 9)

what is the correct answer to this problem

I got 59 when i entered it on my sci-calculator

But my friend got a different answer
of 15

15 is correct.

On an algebraic calculator which allows the use of parentheses, the expression
(3 + 2(8 + 5 • 2 ÷ 4) – 9)
should be entered as
3+2X(8+5X2÷4)-9=
where the first multiplication sign (X) is implicit in the given expression.

If your calculator is the older type that does not accept parentheses, you will have to break down the expression according to the priority of calculations and enter it as:
5X2÷4+8=X2+3-9=

This way, you should get 15 using both types of calculators.

In the future, if you post questions concerning results using calculators, it would help if you could include the make and model of the calculator you used.