Question 32238
1)=24x(2a+3)+7(2a+3)
=(2a+3)(24x+7)
2)= 6.75E-11
3)=4x^2-10x+25
4)18x^2+50 = 2(9x^2+25)
Comment: 9x^2+25 is factorable using complex 
numbers.  I am not sure you have studied those
so I will leave the problem as it is.
Cheers,
Stan H.