You have $15.00 and each shirt you bought was $4.25
$4.25x3=$12.75
$15.00-$12.75= $2.25
So your shorts were $2.25
When competing the square, you want to have

at the end, and using the fact that the x term and coefficient are really

, we see that the third option is the most efficient way to start
1.625 or/and 13/8 should be your answer
The formula for surface area are 2(LW+LH+WH). If the numbers were being placed in the formula, it will become 2[(9*7)+(9*12)+(12*7)]. 9*7 is 63, 9*12 is 108, 12*7 is 84 and the sum will be 255, and multiply by 2 is 510.
The answer is 510