2. Aim: Rationals w/ Unlike Denominators Course: Adv. Alg. & Trig. Do Now: Aim: How do we Add and Subtract Algebraic Fractions that have different denominators? Method 2 Find the lowest common denominator Method 1 Find a common denominator by multiplying the denominators

3. Aim: Rationals w/ Unlike Denominators Course: Adv. Alg. & Trig. Finding the LCD Find the LCD xy; yz2x + 1; 4x 2 - 1 LCD of Numbers LCD of Variable Expressions Each LCD includes all the factors of both denominators LCD of 4 & 6LCD of 4x & 6x 2 xy = x · y yz = y · z LCD = x · y · z (2x + 1) = (2x + 1) 4x 2 – 1 = (2x +1)(2x - 1) LCD = (2x + 1)(2x – 1)

4. Aim: Rationals w/ Unlike Denominators Course: Adv. Alg. & Trig. Finding the LCD LCD = xyz LCD = 1(x – y)

5. Aim: Rationals w/ Unlike Denominators Course: Adv. Alg. & Trig. Finding the LCD x 2 = x · x xy= x · y y 2 = y · y LCD= x · x · y · y = x 2 y 2 Find the LCD x2y2x2y2

6. Aim: Rationals w/ Unlike Denominators Course: Adv. Alg. & Trig. Finding the LCD 3x-6 = 3(x-2) 2x-4 = 2(x-2) LCD = 3(x-2)2 = 6(x-2) = 6x - 12 Factor the Denominators Find the LCD LCD - 6(x-2)

7. Aim: Rationals w/ Unlike Denominators Course: Adv. Alg. & Trig. Finding the LCD x 2 – 36= (x – 6)(x + 6) 3x – 18= 3(x – 6) LCD= 3(x - 6)( x + 6 ) Factor the Denominators Find the LCD 3(x - 6)( x + 6)

8. Aim: Rationals w/ Unlike Denominators Course: Adv. Alg. & Trig. Finding the LCD x 2 – 36 = (x – 6)(x + 6) 3x – 18 = 3(x – 6) LCD = 3(x - 6)( x + 6 )

9. Aim: Rationals w/ Unlike Denominators Course: Adv. Alg. & Trig. Application Problem An electrical conductor is any piece of material that allows electricity to flow through it. Resistance is measured in units called OHMS. A resistor is an electrical conductor that is manufactured to have a certain resistance. If two resistors are connected in parallel, the the resistance of the combination R is given by the formula where R 1 and R 2 are the resistances of the resistors. What is the effective resistance of a 30-ohm resistor and a 20-ohm resistor that are connected in parallel? Parallel flow R1R1 R1R1