[tex] \bf \blue{(a - b) {}^{2} = {a}^{2} - 2ab + {b}^{2} }[/tex]
[tex]3(2x - 5) {}^{2} + 6 = 4 \\ 3({(2x)}^{2} - 2 \times 2x \times 5 + 5 {}^{2} ) + 6 = 4 \\ 3(4x {}^{2} - 20x + 25) + 6 - 4 = 0 \\ 3 \times 4x {}^{2} - 3 \times 20x + 3 \times 25 + 2 = 0 \\ 12x {}^{2} - 60x + 75 + 2 = 0 \\ 12x {}^{2} - 60x + 77 = 0[/tex]
{a=12
{b= - 60
{c=77
delta= b²- 4ac= (-60)²-4•12•77=3600-3696
delta= - 96 <0
delta<0 → ecuația NU are soluții reale!!!!!
