Answer is -pi
Let x be this unknown number. Adding on x to pi gets us the expression x+pi
If we set x+pi equal to zero (which is a rational number) and solve for x, we get
x+pi = 0
x+pi - pi = 0 - pi
x = -pi
so adding pi to -pi will lead to 0 since
x+pi = -pi+pi = 0
A rational number is any number that can be represented as a fraction. (7=7/1 or 52 = 26/1 ).
An irrational number is a number like 3.14159 (pi) or anything like that.
SIMPLE math 120+(2x+30)+x=180
150+2x+x=180
150+3x=180
3x=30
x=10