Question

Semnele radacinilor 2x*2-8x+7=0

Answer 1

Răspuns:

$2*x^{2} -8x+7=0$

Δ=$b^{2} -4ac$

a=2,b=-8,c=7

Δ=(-8)²-4*2*7

Δ=64-56

Δ=8

√Δ=2√2

x1,2=-b±√Δ/2a

x1=8+2√2/4

x1=2(4+√2)/4

x1=4+√2/2

x2=4-√2/2

x| -∞ ................4-2√2...........4+2√2...........+∞

f(x)|.....↓↓↓↓.......0 ....↑↑↑↑↑...0.....↓↓↓↓↓....