Question

cum se rezolva?x la puterea 2 +5x=84

Answer 1

$x^{2}$+5x-84=0
Δ=b² -4ac=25 +4*84=361
b=5
a=1
c=-84
x1= (-b+√Δ)/2a
x1=(-5+√361)/2
x1=(-5+19)/2
x1=14/2
x1=7

x2=(-b-√Δ)/2a
x2=-24/2
x2=-12
solutie x = {7 ; -12}