✔ 最佳答案
You must first figure out what times what equals in this case (-16)
So we have 4X-4=-16 and -8X2=-16 so know we know that one of these is our answer. Then you must figure out what plus what equals 18 or in this case what minus what equals 18. then you must find out what is Squared.
therefore the answer is
9x^2+18x-16
(3x+8)(3x-2)
Now check it
3x*3x=9x^2
8*3x=24
3x*-2=(-6) and lastly
8*-2= -16
so 9x^2+24x-6x-16=9x^2+18x-16