Answer:

Step-by-step explanation:
Given the information, create the following augmented matrix:
The first order was for 1 tray of club sandwiches, at a cost of $9. The second-order, which cost $69, was for 5 trays of club sandwiches and 4 trays of vegetarian sandwiches.

Into an augmented matrix:

Solve.
Let x be the cost of a tray of club sandwiches.
Let y be the cost of a tray of vegetarian sandwiches.
Answer:
x=√2, x=-√2, x= 3 and x=-3
Step-by-step explanation:
We need to solve the equation x^4 - 11x^2+18=0
We can replace x^4 = u^2 and x^2 = u
So, the equation will become
u^2 -11u+18 = 0
Factorizing the above equation:
u^2 -9u-2u+18 =0
u(u-9)-2(u-9)=0
(u-2)(u-9)=0
u=2, u=9
As, u = x^2, Putting back the value:
x^2 =2 , x^2 =9
taking square roots:
√x^2 =√2 ,√x^2=√9
x=±√2 , x = ±3
so, x=√2, x=-√2, x= 3 and x=-3
The answer would be D, 16.8 ft.^2
4 x 2.5 + 2^2 x 3.14 x .5= 16.8
There are 45 minutes in 3/4 of an hour.
10-20-30-40-50-60-70-80-90-100
They are all going up by tens