Step-by-step explanation:
(7 + 3) + (6 -)
= 7 - 6 + 3
= 1 + 3
= 4
The two posts are parallel lines. The ground is a transversal.
The angles measuring 4x and 75 are same side interior angles, so they are supplementary. Their measures add up to 180.
4x + 75 = 180
4x = 105
x = 26.25
The sum will be:
sigma(i = 1 to infinity, 30*(2/5)^i)
->

Which is equal to 30/(3/5) = 50
For solving this we need the change in distance and the change in time. You said that the change in time is 1.8 seconds and the change in distance is 3.6 meters. ( This is assuming it started at 0 meters and started at 0 seconds )
Since the starting was 0,0 we can toss them out as they add no value. Now since speed is labeled (in this case) m/s, we divide how many meters it traveled over how many seconds it took to travel it.
3.6 / 1.8 = 2
The average speed of the cart is 2 m/s
The answer is the first choice: 7, 15, 20.
When you want to know what three numbers can make up a triangle. All you have to do is take the first two numbers and add them up. If the sum is larger than the third number, it can form a triangle. If the sum of the first two numbers are smaller than the third number, it cannot form a triangle.
Hope this helped