Answer:
6x²-21=-5x
6x²+5x-21=0
6x²+5x-21=0
coefficient values: a=6, b=5, c= -21
Δ=b²-4ac= (5)²-4(6*-21)=529
Δ is strictly positive, so the equation 6x²+5x-21=0 has two solutions.
(-b-√Δ)/2a =(-5-23)/12=-7/3
(-b+√Δ)/2a =(-5+23)/12=3/2
solutions of the quadratic equation 6x²+5x-21 : -7/3, 3/2
Explanation: