Question 139153
12x^2-10x-42=0
2(6x^2-5x-21)=0
2(2x+3)(3x-7)=0 
2x+3=0
2x=-3
x=-3/2 answer.
3x-7=0
3x=7
x=7/3 answer.
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12x^2-10x-42=0
(4x+6)(6x-14)=0
4x+6=0
4x=-6
x=-6/4
x=-3/2 answer.
6x-14=0
6x=14
x=14/6
x=7/3 answer.
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12x^2-10x-42=0 
using the quadratic equation:{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}  we get:
x=(10+-sqrt[-10^2-4*12*-42])/2*12
x=(10+-sqrt[100+2016])/24
x=(10+-sqrt2116)/24
x=(10+-46)/24
x=(10+46)/24
x=56/24
x=7/3 aanswer.
x=(10-46)/24
x=-36/24
x=-3/2 answer.