Question

Resolva a equação do 2 grau em IR
x(x=1)=30

Answer 1

$b) x(x+1)=30\\\\ x^{2} +x-30=0\\\\ a=1;b=1;c=-30\\\\\\ \Delta=b^2-4ac\to \Delta=1^2-4*1*(-30)\to \Delta=1+120\to \Delta=121\\\\ x' \neq x''\\\\\\x= \frac{-b\pm \sqrt{\Delta} }{2a} \to x= \frac{-1\pm \sqrt{121} }{2*1} \to x= \frac{-1\pm 11 }{2} \to\\\\\\x'= \frac{-1+11 }{2} \to x'= \frac{10 }{2} \to x'=5\\\\\\ x''= \frac{-1-11 }{2} \to x''= \frac{-12 }{2} \to x''=-6\\\\\\\\ S=(-6;5)$