Consider first the general case of the equation
The general formula that solves this problem is given by
In this case, the number of real solutions depends on the value that is inside the square root. For it to have a real value, it must happen that
So first, let's check if this is our case. In our case a = 2, b = 3 and c = -20.
Then
So in this case, the equation has real values. Now, recall that
So our general solution becomes
Then,
The symbol in the middle means that we get one different solution whenever we take either the plus sign of the minus sign. So the first solution would be
And the other solution would be