The perimeter of a rectangle is 40 units. one side of the rectangle is 7 and the other is x+2. what's the value of x?

Find the sum of 4x^{2} -4+6 and -7^{2} +3x+1

Which value of c would make he following expression completely factored? 8x+cy

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g