Rhonda is purchasing fencing to go around a rectangular lot which is 4x+9 ft long and 3x-5 ft wide which expression represents the amount of fencing she must buy

just sum

10 + 10 = 20

step-by-step explanation:

assume that you have 3 different side lengths.   apply the pythagorean theorem here:   square each of the two shortest sides; call them a and b, so that their squares are a² and b².   also square the longest side, calling the result c².

now, if a² + b² = c² is true, the triangle is a right triangle; otherwise it is not a right triangle.