Question

x²+(x+1)²=85 problema de 2°grau

Answer 1

$x^2+(x+1)^2=85\\x^2+x^2+x+x+1-85=0\\2x^2+2x-84=0$

Coeficientes: a = 2, b = 2 e c = -84

$\Delta=b^2-4ac\\\Delta=2^2-4\cdot2\cdot(-84)\\\Delta=4+672\\\Delta=676$

$x=\frac{-b+-\sqrt{\Delta}}{2a}\\\\x=\frac{-2+-\sqrt{676}}{2\cdot2}\\\\x=\frac{-2+-26}{2}\\\\x_1=\frac{-2+26}{2}=\frac{24}{2}=12\\\\x_2=\frac{-2-26}{2}=\frac{-28}{2}=-14$



Espero ter ajudado.
Bons estudos! :)