Question

1)5х²-14х+8=0      2)3х²-10х+7=0
3)9х²-12х+4=0      4)-4х²-12х+7=0

Answer 1

$a) x_{1,2} = frac{14+- sqrt{196-4*5*8} }{2} = left { {{x=10} atop {x=4}} right.$