Question

cat face4x(7+x)-18 mai mareca15

Answer 1

4x(7+x)-18=
=28x+4x²-18=
=4x²+28x-19  (ecuatie de gradul II)

Δ=708
x1=$\frac{-18+ \sqrt{708} }{8}$
x2=$\frac{-18- \sqrt{708} }{8}$
x1,x2 sunt solutiile ecuatiel

Answer 2

(7+x)=18/4
(7+x)=4,5
x=4,5+7
x=11,5 
Proba 
4x(7+11,5)-18=56 este mai mare decat 18