8²+9(12÷3×2)-7 well we are going to start in the parentheses and do order of operations so 12÷3=4 then 4×2=8 so you have 8² +9(8)-7 well we still need to get rid of the parentheses 9×8=72 so then we are left with 8²=72-7 so now we have to get rid of the exponents so8²=64 64+72-7 136-7=129 so 129 is your answer to the first one.
the second one is easy. its a single step equation. you are trying to get x by itself. so you have 7x=42. you want to get rid of the seven so you have to do the opposite of what it is doing to x. the 7 is multiplying by the x. So whats the opposite of multiplication... division. so you have to divide both sides by 7. so you have 7÷7x=42÷7 now simplify and you have x=6
