How do I expand 2 sets of brackets to make a quadratic?
The FOIL method should be used to expand 2 sets of brackets. FOIL stands for: FIRST, OUTSIDE, INSIDE, LAST. Here is the foil method used without numbers; this creates a general formula. Expanding (x+a)(x+b). First step: FIRST - multiply the first thing in each bracket together, here multiply x by x, which equals x2. Second step: OUTSIDE - multiply the 2 outside values together, here multiply x by b, which equals bx. Third step: INSIDE - multiply the 2 inside values together, here multiply a by x, which equals ax. Fourth step: LAST - mutiply the last thing in each bracket together, here multiply a by b, which equals ab. Final step: add each of these values together. (x+a)(x+b) = x2+bx+ax+ab. A further example of this with numbers included e.g. (x+1)(x+2) = (xx)+(x2)+(x1)+(12) = x2+2x+x+2 = x2+3x+2
