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Foil. One of my favorite math concepts!!. Review. How do you solve this: 5x 2 (3x + 7) Distribute!! 15x 3 + 35x 2 How about this one: (3x + 7)(x 2 + x – 4) Distribute!!! 3x 3 + 3x 2 – 12x + 7x 2 + 7x – 28 Combine like terms 3x 3 + 10x 2 – 5x - 28. FOIL.
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Foil One of my favorite math concepts!!
Review • How do you solve this: • 5x2(3x + 7) Distribute!! • 15x3 + 35x2 • How about this one: • (3x + 7)(x2 + x – 4) Distribute!!! • 3x3 + 3x2 – 12x + 7x2 + 7x – 28 Combine like terms • 3x3 + 10x2 – 5x - 28
FOIL • We are going to do the same thing, but the problems look a little different. • How do we handle this: (x – 5)(x + 2) • We still distribute, but we need a way to keep track of what we did. • FOIL helps you keep track of the multiplication. This is the order: F– First Terms O – Outer Terms I– Inner Terms L– Last Terms
FOIL (x – 5)(x + 2) x2First Terms Put it together: x2 + 2x – 5x – 10 Combine like Terms: x2 - 3x - 10 (x – 5)(x + 2) 2x Outer Terms (x – 5)(x + 2) -5x Inner Terms (x – 5)(x + 2) -10 Last Terms
Foil • Remember this is just a way to keep track of your multiplication. • First Terms • Outer Terms • Inner Terms • Last Terms • Then, combine like terms.
FOIL • Watch me one more time. (x – 7)(2x + 3) F 2x2 O 3x I -14x L -21 Combine like terms 2x2 – 11x - 21 2x2 + 3x – 14x - 21
FOIL • Give these a try. You can check with your neighbors to see if you are right. 1. (x – 5)(x – 4) 2. (x + 6)(x + 2) 3. (x – 3)(x + 2) 4. (2x – 7)(x – 4) 5. (3x – 7)(x + 4) 6. (3x – 4)(2x + 8)
Foil • Did you get them right?? • x2 – 9x + 20 • x2 + 8x + 12 • x2 – x – 6 • 2x2 – 15x + 28 • 3x2 + 5x – 28 • 6x2 + 16x -32
FOIL • How did you do? • Hope it was great! • Tomorrow we will review everything we have done so far and take a quiz!!!