Here, I'll do the first one for you.
When they are talking about a number, use "x".
Since it says twice a number, you say 2x. Or 3x for three times the number
2x+12=3x-31
Then use algebra to find x. Get the numbers on one side and all the x's on the other.
2x+12+31=3x-31+31
2x+43-2x=3x-2x
x=43
Now do the rest on your own!
To find the volume of a rectangular prism, multiply its 3 dimensions: length x width x height. The volume is expressed in cubic units.
Answer:
The speed will be "144 mph".
Step-by-step explanation:
Let the speed of the plane be "x mph".
then,
The car's speed be "x-130 mph".
According to the question,
⇒ 
By applying cross-multiplication, we get
⇒ 
⇒ 
⇒ 
⇒ 
⇒ 
⇒