Question

(5-b)(5+b)-2b(b-3). -5y(y+3)+(y-4)в 2 степени. 3(x-2)в 2 степени -3xв 2 степени

Answer 1

$(5-b)(5+b)-2b(b-3)=25-b^{2}-2b^{2}+6b=25-3b^{2}+6b \\ -5y(y+3)+(y-4)^{2}=-5y^{2}-15y+y^{2}-8y+16=-4y^{2}-23y+16 \\ 3(x-2)^{2}-3x^{2}=3(x^{2}-4x+4)-3x^{2}=3x^{2}-12x+12-3x^{2}= \\ =12-12x$