What is an addition equation for 20-(-10)?

Solve the system of equations y= 3/2 - 1, -x+ y =-3

Given that y varies directly to the square root of (x + 1), and that y = 1 when x = 8,(a)express y in terms of .x,(b)find the value of y when x = 3,(c)find the value of x when y = 5.

The area of each triangle is 7 square units. the surface area of the triangular prism is