Respuesta :

Answer:21x^2-16x-16

Step-by-step explanation:

(3x)(7x)+(3x)(4)+(−4)(7x)+(−4)(4) =

21x^2+12x−28x−16

21x^2−16x−16

Answer:

21x^2 -16x -16

Step-by-step explanation:

This is a basic multiplication question,

We all know that (a+b)(c+d)=ac+ad+bc+bd

Here,

a = 3x

b = -4

c = 7x

d = 4

Therefore,

3x*7x + 3x*4 + (-4)*7x + (-4)*4

=> 21x^2 +12x - 28x -16

=> 21x^2 -16x -16