Answer: 20.75
Step-by-step explanation: Using the order of operations (i.e. GEMS), combine the numbers inside the parentheses within the brackets first (hence G for groupings in GEMS).
[3(4.25+3)+2(7)]-15=
[3(7.25)+2(7)]-15
Still looking at the numbers within the brackets, evaluate 3x7.25 and 2x7 (the M for multiplication/division in GEMS).
[3(7.25)+2(7)]-15=
[21.75+14]-15
Next, add the numbers within the brackets (the S for subtraction/addition in GEMS).
[21.75+14]-15=
35.75-15
Lastly, evaluate 35.75-15, which should get you an answer of 20.75.
35.65-15=
20.75