Question

x(x+1)+(x+1)(x+2)=98 va rog sa-mi dati un raspuns

Answer 1

x² + x + x² + 2x + x + 2 = 98
2x² + 4x - 96 = 0
x² + 2x - 48 = 0
Δ = 4 + 4 x 48 = 196
x1 = (-2 + 14)/2 = 12/2 = 6
x2 = (-2 - 14)/2 = -16/2 = -8

Answer 2

x(x+1) + (x+1)(x+2) = 98      dau factor comun pe ,,x+1"  !

  (x+1)(x+x+2) =98

  (x+1)(2x+298

  (x+1)*2*(x+1) = 98

  2 * (x+1)² = 98    | :2

       (x+1)² = 49   ⇒  x+1 = $\pm7$

                         deci x₁ = -1+7 = 6   si   x₂ = -1-7 = -8 

Proba:  ptr. x=6  =>  6*7 + 7*8 = 42+56 = 98 (A)

                    x=-8 => (-8)(-7) + (-7)(-6) = +56+42 = 98 (A)