Answer:

Step-by-step explanation:




, which is our answer.
Hope this helps!
Answer:
A. 3x^2+7x^2+2×3x ×7-84x = 3x^2+7x^2-2×3x×7
9x^2+49x^2+42x-84 x= 9x^2+49x^2-42x
9x^2+49x^2-42 = 9x^2+49 x^2-42x
verified
B.
X=5
This is because you divide 20/4 since you divide 4 from each side.