Justification for each step in the solution to the equation 6x-9=45

Parabolas y=−2x^2 and y=2x^2 +k intersect at points a and b that are in the third and the fourth quadrants respectively. find k if length of the segment ab is 5.

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?

The sum of two numbers is 0. twice the smaller number subtracted from 3 times the larger number is 10. let x represent the larger number and y represent the smaller number. what is the equation