Answer:
Explanation:
I believe your 6x^2-5+-21=0 should be 6x^2 - 5x - 21=0.
Let's use the quadratic formula to solve for x.
Here the coefficients are a = 6, b = -5 and c = -21.
The discriminant is b^2-4ac, which here is (-5)^2 - 4(6)(-21), or 529.
The square root of 529 is 23.
Thus, the roots (solutions) are:
-(-5) ± 23 28
x = ----------------- = ------ = 7/3 and also x = -3/2
2(6) 12