Problem 11) Start with set U = {1,2,3,4,5} and cross off 1,2,3 to be left with A' = {4,5}. We basically erase everything found in set A. You have the correct answer. Nice job.
Problem 12) Start with U = {1,2,3,4,5} and erase '5' to be left with {1,2,3,4}. So B' = {1,2,3,4}. You are correct here as well.
I can't help with the other problems since either letters, numbers or symbols are missing. Please make a new post and provide those updates.
The general equation given is x^2 - 4x + y^2 = -3. Transform this to an equation of a circle of the form x^2 + y^2 = r^2.
Use completing the square method:
x^2 - 4x + 4 + y^2 = -3 + 4
(x - 2)^2 + y^2 = 1
the center of the circle is (2,0) and r = 1
To check if it intersects the y axis, find the value of the x-intercept.
This is a word problem signifying an algebraic expression.
Translating this to mathematics:
add 4 to both sides.
divide 16 to both sides.
this is:
Write the first ratio as 11/100 and set it equal to 22/n.
since 11 x 2=22 you can multiply 100 x 2 and you'll get 200.
*Check*: 11% of 200=22
