[latex](2-b)^2=2^2-2cdot2cdot{b}+b^2=4-4b+b^2[/latex] [latex](3x+4)^2=(3x)^2+2cdot3xcdot4+4^2=9x^2+24x+16[/latex] [latex](3x-2y)^2=(3x)^2-2cdot3xcdot2y+(2y)^2=9x^2-12xy+4y^2[/latex] [latex](3x+5)(3x-5)=(3x)^2-5^2=9x^2-25[/latex]

(2-b)^2 = 4-4b+b^2 (3x+4)^2=9x^2+24x+16 (3x-2y)^2=9x^2-12y+4y^2 (3x+5)(3x-5)=9x^2- 25