3(2x + 7) = 9 ...divide both sides by 3
2x + 7 = 9/3
2x + 7 = 3
2x = 3 - 7
2x = -4
x = -4/2
x = -2
or this way..
3(2x + 7) = 9
6x + 21 = 9
6x = 9 - 21
6x = - 12
x = -12/6
x = -2
Answer:
C. 22 sq. ft
Step-by-step explanation:
* 4
11 ÷ 2 = 5.5
5.5 * 4 = 22
The area of the trapezoid is 22 square feet
Step-by-step explanation:
Old Railroad Car:
- 1 day of coal in 15 hours
- 1/15 days of coal in 1 hour
New Railroad Car:
- 1 day of coal in 10 hours
- 1/10 days of coal in 1 hour
Total number of days of coal in 1 hour
= 1/15 + 1/10 = 1/6.
Since there is 1/6 days of coal in 1 hour,
there will be 1 day of coal in 6 hours.
It will take them 6 hours to transport the supply.
