a)
(x+5)^2=x^2+2*x*5+5^2=x^2+15x+25
b)
(2a+3b)^2=(2a)^2+2*2a*3b+(3b)^2=4a^2+12ab+9b^2
c)
(7xy+11)^2=(7xy)^2+2*7xy*11+11^2=49x^2y^2+154xy+121
d)
(2x+7y)^2=(2x)^2+2*2x*7y+(7y)^2=4x^2+28xy+49y^2
e)
(4ab+5cd)^2=(4ab)^2+2*4ab*5cd+(5cd)^2=16a^2b^2+40abcd+25c^2d^2
wzór skróconego mnożenia
(a+b)^2=a^2+2ab+b^2