Question

(x+11)²-(x-7)(x+7) при x=31​

Answer 1

$(x+11)^2-(x-7)(x+7);\,\,\,\,\,\, x=31\\\\(x+11)^2-(x-7)(x+7)=x^2+22x+121-(x^2-49)=x^2+22x+121-x^2+49=22x+160=22\times31+160=682+160=842$