Question 39580
1) 8x^3+8x^2-6x
=2x(4x^2+4x-3)
=2x(2x-1)(2x+3)

2) 24x^2-92x+80
4(6x^2-23x+20)
=4(?)
Use quadratic formula to get:
x=[23+-sqrt(1009]/12
=4(x-(23+sqrt(1009)]/12)(x-(23)-sqrt(1009))/12)
3) 6x^2+13x+6=0
x=[-13+-sqrt25]/12

4) 2(a^2+9)=15a
2a^2+18-15a=0
2a^2-15a+18=0
*[invoke quadratic "a",2,-15,18]
Hope this helps.
Cheers,
Stan H.