Question

Calculati : (a+2)(a-2), (x+1)(x-1) , (7-y)(7+x) , (x+3)(x-3) ,(x+0,5)(x-0,5) , (x+y)(x+y)

Answer 1

a²-4
x²-1
49-y²
x²-9
x²-0,25
x²+2xy+y²

Answer 2

(A+2)(a-2)= a la a doua - 2 la a doua = cu a la a doua minus 4
(x+1)(x-1) = x la a doua minus 1 la a doua = x la a doua -1
(7-y)(7+y) = 7 la a doua -y la a doua = 49 - y la a doua
(X +3)(x-3) =x la a doua - 3 la doua = x -9
(X+y)(x+y) = x la a doua plus xy plus yx plus x la a doua
(X+0,5)(x-0,5) = x la a doua minus 0,5 la a doua = x la a doua minus 0,25