4(5x-20)= -20
20x-80= -20
+80 +80
____________
20x=60
_______
20
x=3
After the first, we have 2/3 left, the second and third took 1/6 and 1/4, or 5/12 (1/6+1/4=2/12+3/12=(2+3)/12=5/12). Now, we just subtract 5/12 from 2/3, so 2/3-5/12=8/12-5/12=(8-5)/12=3/12=1/4. This means we have 1/4 of an hour left.
ANSWER:
2.33 foot
STEP-BY-STEP EXPLANATION:
We can calculate the distance from the staircase to the wall, by means of the trigonometric cosine ratio, which is the following:

Replacing and solving for x:

The distance would be 2.33 foot
I believe it is -8y + 5x - 3
Answer:
49N
Step-by-step explanation:
Step one
Given
When the force of 63 N acts on a certain object
the acceleration of the object is 9/ms^2
Firstly, we need to calculate the mass m
F=ma-------1
m= F/a
m= 63/9
m= 7kg
Step two:
Also, if the acceleration of the object becomes 7 m/s^2
then the force
Note: the mass remains the same= 7kg
F=ma
F=7*7
F= 49N