Answer:
21 is the answer for that
So QRS equals to 158 degrees. Therefore, you need to do 8x+8+2x=158. This is so then you can find x. In order to find x, you'll need to combine the 2x and 8x(10x+2=158). Then subtract 2 from both sides(10x=156). Finally divide by 10(x=15.6). In order to find TRS, multiply 15.6 by 2 to get the angle measure. If you want to find QRT, plug 15.6 into the equation(multiply 8 and 15.6 and add 8=132.8)
Well I don't get what the other parts of the question is asking, but they can make 240 packs of pencils.
The correct answer of

if x=4 is 272.
to solve the equation if x equals 4, you must substitute the x of the 4.

then solve by order of operations.
solve what is inside the parentheses first

then do the multiplication of the factors

then the final step, adding, to get the solution of 272
To minimize the cost, we take the straight distance from the refinery to the other side of the river as 2 km. Also, the 7 km will be the distance that has to be traveled by the pipeline in land. The total cost, C, is therefore,
total cost = (2 km)($800,000/km) + (7 km)($400,000 /km)
total cost = $4,400,000
Thus, the total cost of the pipeline is approximately $4,400,000.00.