A quadtriatel is said to contain perpendicular diagnols if four go 90 degree angles are formed at the intersection of these lines
7.
(2b^2+7b^2+b)+(2b^2-4b-12)
(9b^2+b)+(2b^2-4b-12)
9b^2+b+2b^2-4b-12
11b^2+b-4b-12
11b^2-3b-12
8.
(7g^3+4g-1)+(2g^2-6g+2)
7g^3+4g-1+2g^2-6g+2
7g^3-2g-1+2g^2+2
7g^3-2g+1+2g^2
7g^3+2g^2-2g+1
Hope this helps!
ANSWER
Paul and Matt will take

to install the floor working together.
EXPLANATION
First, calculate Paul's rate, which is

Next, calculate Matt's rate, which is,

Let us assume that, Paul and Matt took

to do the work together.
Then, the rate of working together is,

Now, add the individual rates and equate to the rate of working together to form an equation that will help us solve for x.

Simplify the left hand side


We reciprocate both sides to get (You could have also done cross multiplication).

1lbs is 16oz, so do the math: 16x3 is 48. 3lbs is 48oz, meaning this is false.
Answer: a) 
Step-by-step explanation:
Since we have given that

a.) Find the inverse of f(x) and name it g(x).
Let f(x) = y
So, it becomes
Switching x to y , we get


b) . Use composition to show that f(x) and g(x) are inverses of each other.

Similarly,

so, both are inverses of each other.
c) Draw the graphs of f(x) and g(x) on the same coordinate plane.
As shown below in the graph , Since for inverse function we need an axis of symmetry i.e. y=x
And both f(x) and g(x) are symmetry to y=x.
∴ f(x) and g(x) are inverses of each other.