Multiply the parenthesis by 6:
-7x+6x-492-2(x+3)+10
Multiply the parenthesis by -2:
-7x+6x-492-2x-6+10
Calculate the sum of similar terms:
-3x-492-6+10
Calculate the sum or difference:
-3x-488
Answer:
500cm x 300cm
It's probably A (I can't tell you for certain, because I can't see the image, but the other options seem illogical).