How do you simplify the expression #5(2y-5)(2y+5) -4(y-2)(y+3) - (2y+1)^2#?

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Answer 1 · 2017-02-21T16:07:40

#12y^2-8y-102#

Since

#(a-b)(a+b)=a^2-b^2#

and

#(a+b)(c+d)=ac+ad+bc+bd#

and

#(a+b)^2=a^2+2ab+b^2#

you would expand the expression:

#5(4y^2-25)-4(y^2+3y-2y-6)-(4y^2+4y+1)#

and multipy:

#20y^2-125-4y^2-12y+8y+24-4y^2-4y-1#

Then let's sum the like terms:

#12y^2-8y-102#