 Let's try to solve 2x squared plus 5x equals 12. We'll use the quadratic formula. First, we'll have to rewrite the equation so it equals zero. So we have our equation 2x squared plus 5x equals 12. We don't want it to be equal to 12, so we'll subtract 12 from both sides. And that gives us our new equation 2x squared plus 5x minus 12 equals zero. Now we'll apply the quadratic formula. The equation ax squared plus bx plus c equals zero has solutions x equals negative b plus or minus squared b squared minus 4ac over 2a. In order to use the quadratic formula, we have to fill out the form. We need to know what a, b, and c are equal to. So a is the coefficient of x squared, so for our equation, a equals... b is the coefficient of x, so in our equation, b is equal to... and c is the constant term, so in our equation, c is equal to... equals means replaceable, so every place I see a, I'm going to replace it with 2. Everywhere I see b, I'll replace it with 5. And every place I see c, I'll replace it with negative 12. And at this point, I'll do a whole bunch of arithmetic. Now remember this plus or minus means that we'll either add or we'll subtract. And so that means I'll actually have two solutions here. Minus 5 plus 11 over 4 or minus 5 minus 11 over 4. And we'll simplify this a little bit. And remember, if it's not written down, it didn't happen. We can summarize what we did. We used the quadratic formula. We filled in our values and we got 3 halves or negative 4.