x(x+2)=0
how do you turn a number to zero? you multiple it by zero. since we have multiplication on the left, one of the multiplied numbers has to be 0. this leads to 2 possible answers:
I. x=0. which is the first answer.
II. x+2=0 . decrease both sides of the equation by 2
x+2=0 \-2
x=-2 . that's the second answer.