Объяснение:

[tex](a+5)^2=a^2+2*a*5+5^2=a^2+10a+25\\(3y-x)^2=(3y)^2-2*3y*x+x^2=9y^2-6yx+x^2\\(2b-1)(2b+1)=(2b)^2-1^2=4b^2-1\\(4a+3b)(4a-3b)=(4a)^2-(3b)^2=16a^2-9b^2[/tex]