Question

Calculati:
a)(x-1)(x+2)+(3x-1)(2x+5)-3x(x+1)=
b)(x-7)(x+3)-(x+1)(x+2)+(5-x)(x-4)=
c)(a-b)(a+3b)+(2a-b)(a+2b)-(a+b)(a-2b)=
d)(2-x)(x+$x^{2}$)-$x^{2}$(3+x)+8+(x+2)(5+$x^{2}$)=

Answer 1

a.= x^{2} + 1x-x-2+6 x^{2} +15x-2x-5-3 x^{2} -3x= 4 x^{2} +11x-7x b. = x^{2} +3x-7x-21- x^{2} -2x-x-2+5x-20- x^{2} +4x= x^{2} -2x+43 c. = a^{2}+3ab-ab-3b^{2}+2a^{2}+4ab-ab-2b^{2}-a^{2}+2ab-ab+2ab=2a^{2}+8ab-3b^{2}. d.2x+2x^{2}-x^{2}-x^{3}-3x^{2}-x^{3}+8+5x+x^{3}+10+2x^{2}=7x-x^{3}+18 X^{2}=x la a doua X^{3}=x la a treia a^{2}=a la a doua 2b^{2}= 2b la a doua ....