A rectangle has a length of (x+3) centimeters and a width of 1/2x centimeters. If the perimeter is 24 cm, what is the length of the rectangle?

Identify reflection rule on a coordinate plane that verifies that triangle a(-1,7), b(6,5), c(-2,2) and a’(-1,-7), b(6,-5), c’(-2,2) triangle are congruent when reflected over the x-axis