Question

Resolva a equacao x2-10x+9=0

Answer 1

$x^2-10x+9=0\\\\ a=1;b=-10;c=9\\\\\\ \Delta=b^2-4ac\to \Delta=(-10)^2-4*1*9\to \Delta=100-36\to \Delta=64\\\\ x' \neq x''\\\\ x= \frac{-b\pm \sqrt{\Delta} }{2a} \to x= \frac{-(-10)\pm \sqrt{64} }{2*1} \to x= \frac{10\pm 8 }{2} \to \\\\\\ x'= \frac{10+ 8 }{2} \to x'= \frac{1 8 }{2} \to x'=9\\\\\\ x''= \frac{10- 8 }{2} \to x''= \frac{2 }{2} \to x''=1\\\\ \\\\ S=\left \{ 1;9\left \}$

Answer 2

∆=B ao quadrado- 4ac
∆=-10 ao quadrado -4*1*9
∆=100-36
∆=64
primeira raiz é -B+√64\2a
-(-10)+8\2
18\2
9
segunda raiz é -(-10)-8\2
10-8\2
2\2
1 outra raiz