Question

Desenvolva os produtos notaveis
(7-y)²

Answer 1

$(7-y)^2\\\\\\ (7-y)*(7-y)\to \\\\ 49-7y-7y+y^2=0\to \\\\ y^2-14y+49=0\\\\ a=1;b=-14;c=49\\\\ \Delta=b^2-4ac\to \Delta=(-14)^2-4*1*49\to \Delta=196-196\to \Delta=0 \\\\ y'=y''\\\\ y= \frac{-b\pm \sqrt{\Delta} }{2a} \to y= \frac{-(-14)\pm \sqrt{0} }{2*1} \to y= \frac{14\pm 0 }{2} \to \\\\ y'=y''= \frac{14}{2} \to y'=y''=7\\\\\\ S=(7)$

Answer 2

(7 - y)²

(7 - y)(7 - y)

49 - 7y - 7y + y²

49 - 14y + y²

y² - 14y + 49