Complete the square on this equation: 2x^2 + 20x + 15 = 0.
First you need to remove the coefficient on the x^2. We do this by factorising the 2x^2 + 20x and placing the 2 from the x^2 outside a set of brackets. This looks like:2(x2+10x) +15 = 0Then we get half of the x coefficient and place it in a secondary set of squared brackets in the form (ax2 +b)2. This looks like:(x + 5)2Next we subtract from this set of brackets the square of the half of the x coefficient. Make sure to keep this within the first set of brackets. This looks like:2((x+5)2-25)+15 = 0This means when the squared brackets are multiplied out, x2 + 10x is the only thing that will be left. Finally we expand the brackets to neaten the equation.2(x+5)2 +2*-25+15 = 02(x+5)2-35=0The equation is now in complete the square form.
