Question

Efectuati (3x-8)(84-x) = ?

Answer 1

252x-3x^2-672+8x=3x^2+260x-672

Answer 2

(3x-8)(84-x) = 252x - 672 - 3x^2 + 8x = -3x^2 + 260x - 672

acum trebuie sa calculezi delta

Δ = 67600 - 8064 ⇒ Δ = 59536
x1 = $\frac{-260+ \sqrt{ \ 59536 } }{6}$ = $\frac{-16}{-6} = \frac{8}{2}$
x2 = $\frac{-260- \sqrt{59536} }{-6} = \frac{-504}{-6} = 84$
 varianta 1
x=x1
12 × 80 = 960
 
 varianta 2
x=x2
244 × 0 = 0