17. (3a2 – 2ab + 3b2) - (-a2 – 5ab + 3b2)
18.
5c – [8c – (6 – 3c)]
19.
10x + [3x – (5x – 4)]
20.
3x 2 – [7x- (4x – x2) + 3]
21.
x2 – [ - 3x+ ( 4 – 7x)]

Aparallel system functions whenever at least one of its components works. consider a parallel system of n components, and suppose each component works independently with probability 0.5. find the conditional probability that component n works given that the system is working

What are the solutions to the equation 4x2+3x=24-x

Which number line represents the solution set for the inequality -1/2x> 24?