( x + 7 )^2 - ( x + 3 )^2

Question

 Perform the indicated operations and simplify completely: 

(x+7)² - (x+3)²

Answer 1

I agreed with Steven's answer up until the third line where you add the two terms.

 

x²+14x+49 - (x²+6x+9) => don't forget to distribute the negative sign into the parenthesis

 

x²+14x+49-x²-6x-9

 

8x+40 is your final answer.

Answer 2

Expand them and collect the like terms.

Expanding the first term you get x^2+14x+49.

Expanding the 2nd term you get x^2+6x+9.

Adding the like terms you get 2x^2+20x+58.

You can factor out a 2 to get 2(x^2+10x+29).