Best Answer: Look at the discriminant of the quadratic equations to find the number and type of solutions. The discriminant is part of the quadratic formula underneath the square root sign: b^2 - 4ac. If it is positive, then there are two real solutions for that quadratic equation. If the discriminant is 0, then there is one real solution. If the discriminant is positive, then there are two imaginary solutions.
1.) x^2 - 18 = 0
a = 1, b = 0, c = -18
b^2 - 4ac
(0)^2 - 4(1)(-18)
72
ANSWER: 2 real solutions
2.) x^2 + 5x + 7 = 0
a = 1, b = 5, c = 7
b^2 - 4ac
(5)^2 - 4(1)(7)
25 - 28
-3
ANSWER: 0 real solutions
Hope this helps
