Answer:
7. 
8. l=11cm and w=7 cm
9. 
10. 
Step-by-step explanation:
Question 7.
The given expression is:

Expand the parenthesis using the distributive property:

Group similar terms:

Simplify

Divide both sides by -10

Question 8:
Let the width of the rectangle be;
The length of the rectangle is 
The perimeter is given as: 
Given that the perimeter P=36, then:
![36=2[(w+4)+w)]](https://tex.z-dn.net/?f=36%3D2%5B%28w%2B4%29%2Bw%29%5D)

Divide both sides by 2:

Subtract 4 from both sides:



The dimensions of the rectangle is: w=7 cm and l=7+4=11cm
Question 9
Let the number be x.
"5 fewer than the number" is written as 
"5 fewer than a number is at least 12" becomes

Question 10:
Let the number be x.
The quotient of a number and 3 is written as:

The quotient of a number and 3 is no more than 15 is written as;

If u meant to put, 5x multipled by 2^3x=21 the answer is x= 0.798
Answer:
2/3
Step-by-step explanation:
So what you do,is you add them together to get 13/10 but then you can also simplify it but you can keep the answer to 13/10
Answer:
Step-by-step explanation:
Set this up as a proportion, with inches on the top and feet on the bottom for our scale. We will find the actual length first, then we'll find the width.

Cross multiply to get that the actual length is 5(2.5) = 12.5 feet. Now for the width:

Cross multiply to get that the actual width is 5(3) = 15 feet.
If you want the area of the room, multiply the length times the width to get
A = 15(12.5)
A = 187.5 feet squared