Answer:
B
Step-by-step explanation:
4x-5y=2 ...(1)
10x-21y=10 ...(2)
(1)+2(2) gives
24x-47y=22
Answer: 9.70%
Step-by-step explanation:
The formula to find the percentage error is given by :-
Given : Actual mass of zinc oxide used by pharmacist = 28.35 g
Estimated mass of zinc oxide used by pharmacist =31.1 g
Now,
i.e.
i.e.
Hence, the percentage of error on the basis of the desired quantity.= 9.70%
n=2
8+8(8-n)=40+8n (distribute 8 through the parenthesis)
8+64-8n=40-8n (add the numbers)
<em>72-</em>8n=40+8n (move the variable to the left side and change its sign)
<em>72</em><em>-</em>8n+8n=40
-8n+8n=40<em>-72</em> (connect like terms)
-16n = -32 (divide both sides by -16)
<u><em>n=2</em></u>