Answer:

Step-by-step explanation:
<u>Ratios
</u>
We are given the following relations:
![a=\sqrt{7}+\sqrt{c}\qquad \qquad[1]](https://tex.z-dn.net/?f=a%3D%5Csqrt%7B7%7D%2B%5Csqrt%7Bc%7D%5Cqquad%20%5Cqquad%5B1%5D)
![b=\sqrt{63}+\sqrt{d}\qquad \qquad[2]](https://tex.z-dn.net/?f=b%3D%5Csqrt%7B63%7D%2B%5Csqrt%7Bd%7D%5Cqquad%20%5Cqquad%5B2%5D)
![\displaystyle \frac{c}{d}=\frac{1}{9} \qquad \qquad [3]](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7Bc%7D%7Bd%7D%3D%5Cfrac%7B1%7D%7B9%7D%20%5Cqquad%20%5Cqquad%20%5B3%5D)
From [3]:

Replacing into [2]:

We can express 63=9*7:

Taking the square root of 9:

Factoring:

Find the ration a:b:

Simplifying:

Answer:
cups plaster of paris.
Step-by-step explanation:
Given:
for one batch of sidewalk chalk =
cup plaster of paris.
Number of bathes = 3
We need to find quantity of plaster of paris.
Solution:
For making 1 batch of sidewalk chalk =
cup plaster of paris.
For making 3 batches of sidewalk chalk =
cup plaster of paris.






Therefore, he needed
cups plaster of paris.
The answer to this question is A, 12. Hope this helps.
To find the intersection points, you take x^2 - 4x + 9 = -2x + 17
This gives x^2 - 2x - 8 = 0,
which factorises to (x - 4)(x + 2) = 0, giving the solutions x = 4 or x = -2
From the graph, we can see that x is positive, meaning x = 4, so a = 4.
Substituting x = 4 into y = -2x + 17, we get y = -2(4) + 17 = 9, so b = 9.
a + b = 4 + 9 = 13. The answer is B.