I'm assuming you mean

Write the 2 as a fraction 2/1 and multiply.
Answer:
x=63
Step-by-step explanation:
The two interior angles add up the the exterior angle, so 51+x+12=2x. From there, solve to get x=63. Hope this helped!
Answer:
12.60
Step-by-step explanation:
To find the tip, take the amount of the bill and multiply by 30%
42 * 30%
Change to decimal form
42 * .30
12.6
Answer:

will give you an explanation if you want tag me on comment.
Answer:
a i the answer
Step-by-step explanation:
l ≤ 12
2l + 2w < 30