D: mathhh again..

[minor thistle]

I don't understand how to do it 💀... not 1 bit. How do u do it?

[latent cradle]

1st is
(x+5)²
(x+5)(x+5)
x²+2(x)(5)+5²

The rest is almost the same

The general formula is
(a+b)²
= a²+2ab+b²

And
(a-b)²
= a²-2AB+b²

a and b are + because of ², cause (-a)²=a²

[minor thistle]

:0 thank you very much🤍

[feral elm]

And for 13-18, the general formula is a²-b²= (a–b)(a+b)

13. (X+7)(x-7) = x²+7²