(b+3)(b-3)=b²-9
(2c-1)(2c+1)=4c²-1
(3-1/5 a)(3+1/5 a)=9 - 1/25 a²=9-0.04a²
(2-x)(2+x)=4-x²
(7p+3)(7p-3)=49p² - 9
(k-y)(k+y)=k² - y²
(x+3y)(x-3y)=x²-9y²
(10a-b)(b+10a)=10a - b²
(2a-b)(2a+b)=4a² - b²
(y+4)(y-4)=y² - 16
(8x+4a)(8x-4a)=64x² - 16a²
9p² - 4=(3p+2)(3p -2)
1 - 25x²=(1-5x)(1+5x)