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;

Answer:

Step-by-step explanation:
Since we have given that
A toy manufacturer claims that the mean time that its top-selling toy captures children's attention is at least 45 minutes.
Since we need to carry out a hypothesis test whether he can refute the claim.
We always take the alternate hypothesis such that it should satisfy the given statement.
And the null hypothesis can be equal to mean or other than that is given in alternate hypothesis.
So, hypothesis :

3r+n2−r+5−2n+2<span />=3r+n2+−r+5+−2n+2=3r+n2+−r+5+−2n+2<span />=(n2)+(−2n)+(3r+−r)+(5+2)<span />=n2+−2n+2r+7<span /><span />
=n2−2n+2r+7
Answer:A
Step-by-step explanation: