Answer:
Your answer is 4x.
Step-by-step explanation:
Add 2+2
Combine your x's (like terms)
then you got 4 from 2+2
Add the leftover x so it makes 4+x then add it will give you 4x.
Answer:

Step-by-step explanation:
the general equation of a circle is

with (h,k) being the centre of the circle and r the radius
Answer:
-1.53 , 1.53
Step-by-step explanation:
It is basically asking you to find the percentiles. so for the bottom 6.3% you would type into your calculator 2nd, VARS, invNorm, area: .063, mean: 0, and Standard Deviation: 1 which gives you -1.53.
for the upper 6.3% you have to take 1-.063=.937 to get the upper percentile. now type into your calculator 2nd, VARS, invNorm, area: .937, mean: 0, and Standard Deviation: 1 which gives you 1.53.
I hope I helped :D
The first solution contributes 0.78*1 = 0.78 L of acid.
The second contributes 0.64*6 = 3.84 L of acid.
There will be 7 L total of the new solution, and 3.84 + 0.78 = 4.62 total L of acid in it. So the new solution has a concentration of 4.62/7 = 0.66, or about 66%.