This is josh’s solution for the equation x2-6x-7=0: x2-6x-7=0 x2-6x=7 x2-6x+9=7+9 (x-3)2=16 x=19 x-3=-16 x=-13 is josh’s solution correct? explain

The perimeter of an equilateral triangle is 4 cm more than the perimeter of a square and the length of a side of the triangle is 8 cm more than the length of a side of the aware. find the length of a side of the equilateral triangle