HELP I NEED HELP ASAP

Acontractor needs 54 square feet of brick to construct a rectangular walkway. the length of the walkway is 15 feet more than the width. write an equation that could be used to determine the dimensions of the walkway. solve this equation to find the length and width, in feet, of the walkway.

The polynomial function of least degree with a leading coefficient of 1 is: f(x) = x3 + ax2 + bx + c

Solve the equation for x.3(6x - 1) = 12 i've tried doing the math and i can't find out what i'm doing wrong