1/3 of 30 would be 10. So 10 students walk to school.
X² +18x = 0
To complete the square we are going to use formula a² +2ab +b² = (a+b)²
x² +2*9*x = 0
x² +2*9x+9² = 9²
(x+9)² = 9²
√(x+9)² = +/-√9²
x+9 = 9, or x+9 = -9
x=0, or x= - 18
The equation could be solved different way
x² +18x = 0
x(x+18) = 0
x=0 or x+18=0
x=0 or x=-18
