Because this is a second degree equation you will have 2 solutions. When you take the square root of a number you have to account for both the positive and negative roots. Since the square root of 289 is 17 then your solutions are +17 and -17.
Because this shape has 2 right angles, we can confirm that it has one set of parallel sides and is a trapezoid. Therefore, use the formula for area of a trapezoid, .5(b1+b2)(h)
.5(1+6)(12)
.5(7)(12)
42 units^2
The answer is 45 :^))))))))))