Find the the roots of −3x2+5x+12=0 by using the quadratic formula.
−43
3
Given equation is −3x2+5x+12=0
On comparing with ax2+bx+c=0, we get
a=-3, b=5 and c=12
By quadratic formula,
x=−b±√b2−4ac2a
=−(5)±√(5)2−4(−3)(12)2(−3)=−5±√25+144−6=−5±√169−6=−5±13−6=8−6,−18−6=−43,3
So, −43 and 3 are two roots of the given equation.