Question

care dintre numerele -7;-5;5;7 sint solutii ale ecuatiei x la a doua+2x-35=0

Answer 1

x²+2x-35=0
x²+7x-5x-35=0
x(x+7)-5(x+7)=0
(x-5)(x+7)=0
⇒x-5=0⇔x=0+5⇔x=5
⇒x+7=0⇒x=0-7⇔x=-7
raspuns:5, -7

Answer 2

x²+2x-35=0
Δ=b²-4ac
=2²-4·1·(-35)
=4+140=144
x1=-2+√144/2=10/2=5
x2=-2-√144/2=-14/2=-7