2a+3c=22.00 ......equation 1
a+4c=18.50 =>2a+8c=37.00 .....equation 2
subtract equation one from equation two:
5c=37-22=15
c=3
a+4*3=18.50 =>a=6.50

for the Hu family: 3*6.50+1*3.00=22.50 dollars

3 0

3 years ago

Which matrix is singular? A. A B. B C. C D. D

anyanavicka [17]

Answer:

D. $\left[\begin{array}{ccc}-12&-4\\9&3\end{array}\right]$

Step-by-step explanation:

In order for a matrix to be singular, the determinant has to be zero.

6 0

3 years ago

Use Vocabulary in Writing

AleksAgata [21]

Answer:

Step-by-step explanation:

So you know that m= $\frac{y}{x}$ . To find that you need to take one y(6) coordinate and subtract the other y(-2) coordinate. So then you put that in the nominator. Then you take the x(2) coordinate from the same pair that you started with the y(6) coordinate and subtract the other x(0). You put that answer in the denominator. That's how you find slope=m. Then you plug slope in the equation.

y = $\frac{8}{2}$ x + b

Then you take on y coordinate and plug it into y.

6 = 4 x + b

Then you insert the x coordinate from the same pair that you did y.

6 = 4(2) + b

Now 4 times 2 is 8 and 8 is not equal to 6. So b must be -2.

You can check it with the other coordinates, and that's how you check your original answer.

I'm in 7th grade hope you found it helpful.

8 0

2 years ago