One way of solving quadratic equations is to use the technique of "completing the square" to rearrange the quadratic into something like a "(squared part) equals (a number)" format. For example:
Step 1: 4x2 – 2x – 5 = 0
Step 2: 4x2 – 2x = 5
Step 3: x2 – 1/2 x = 5/4
Step 4: x2 – 1/2 x + 1/16 = 5/4 + 1/16
Step 5: (x – 1/4)2 = 21/16
Step 6: 
Step 7: 