How do I solve 5x - 4x^2

What is the value of x in the this question ?

What is the ratio of the length of an object in yards to the length of the same object in miles?

Gigi earned $65 for 5 hours of gardening. she earned $90 for 9 hours of office work. which statement correctly compares gigi’s earning per hour for gardening and office work? she earned $3 more per hour for office work than for gardening. she earned $4 more per hour for office work than for gardening. she earned $3 more per hour for gardening than for office work. she earned $4 more per hour for gardening than for office work.