Question

Folositi formulele de calcul prescurtat calculati: a) (x+1) la puterea a2a b)(x+2)×(x-2) c) 3(x-2) la a 2a +5(x+2)×(x+3)

Answer 1

a)(x+1)²=x²+2•x•1+1²
=x²+2x+1
b)(x+2)(x-2)=(x²+2²)=x²+4
c)3(x-2)²=(3x-6)²
=(3x)²-2•3x•6+6²
=9x²-36x+36
=9(x²-4x+4)
=9(x+2)²
x²-4x+4=(x+2)²

Answer 2

a) formula este: a^2+2ab+b^2=> x^2+2*x*1+1^2= x^2+2x+1=0=> delta=2^2-4*1*1=0