The coefficient of x
2
in (x+3)(2−4x)(5x−6) is:

Let's expand the expression step-by-step:
First, multiply the first two terms:

(x+3)(2−4x)=2x−4x
2
+6−12x=−4x
2
−10x+6
Now multiply this result by the third expression (5x−6):

(−4x
2
−10x+6)(5x−6)
To find the coefficient of x
2
, we only need to look at terms that result in x
2
after multiplication:

(−4x
2
)×(−6)=24x
2


(−10x)×(5x)=−50x
2


Summing these up:

24x
2
−50x
2
=−26x
2

Thus, the coefficient of x
2
is −26.