Question

Please help me solve

Answer 1

If the area of a rectangle is width time length, then we have all of the info we need.

the width is 6 less than 3 times the length. let the length be x and put your words into math! 6 less is -6. 3 times a number is 3x, so width=3x-6.

so we have area=l×w which becomes x×(3x-6)=105

solve
$x(3x - 6) = 105 \\ 3 {x}^{2} - 6x = 105 \\ 3( {x}^{2} - 2x) = 105 \\ \frac{1}{3} \times 3( {x }^{2} - 2x) = 105 \times \frac{1}{3} \\ {x}^{2} - 2x = 35 \\ {x}^{2} - 2x - 35 = 0$
factor and solve!

you will get one positive and one negative. pick the positive since lengths cannot be negative