Please help it’s due in 20 minutes and it’s easy i just don’t get it :( i’ll mark as brainiest !!

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Isabel graphed the following system of equations. 2x – y = 6 y = -3x + 4 she came up with the solution (2,-2). what were the 3 steps she did to get that solution? (make sure they are in the correct order)

What percent of 18 is 24? and plz explain thx.