Answer:
$180
Step-by-step explanation:
Since the cost of the telescope with the 30% discount is $126 then $126 is 70% of the original price. Remember 100-30=70. To find the original price set up a proportion with these values:

Solve for the original price by cross multiplying numerator with denominator.
x(70) = 126(100)
70x = 12600
x= $180
First do the parentheses:
16/4+56-8
Then divide:
4+56-8
Then add and subtract from left to right:
60-8
52
Hope this helps.
Volume=Legnth times width times height
legnth=90
height=70
width=40
volume=90 times 40 times 70
volume=3600 times 70
volume=252000
answer is v=252,000 cm^3