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Ex. 6 Solve:. Multiply by common denominator. 2(x – 2) = 3x – (x)(x – 2). 2x – 4 = 3x – x 2 + 2x. x 2 – 3x – 4 = 0. (x – 4)(x + 1) = 0. x = 4, – 1. Ex. 7 Solve: |x 2 – 3x| = – 4x + 6. –( x 2 – 3x) = – 4x + 6. x 2 – 3x = – 4x + 6. – x 2 + 3x = – 4x + 6.
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Ex. 6 Solve: Multiply by common denominator 2(x – 2) = 3x – (x)(x – 2) 2x – 4 = 3x – x2 + 2x x2 – 3x – 4 = 0 (x – 4)(x + 1) = 0 x = 4, – 1
Ex. 7 Solve: |x2 – 3x| = –4x + 6 –(x2 – 3x) = –4x + 6 x2 – 3x = –4x + 6 –x2 + 3x = –4x + 6 x2 + x – 6 = 0 0 = x2– 7x + 6 (x + 3)(x – 2) = 0 0 = (x – 6)(x – 1) x = -3, 2 x = 6, 1 |(-3)2 - 3(-3)| = -4(-3) + 6 |(6)2 - 3(6)| = -4(6) + 6 so 6 not good 18 = 18 so -3 good 18 = -18 |(2)2 - 3(2)| = -4(2) + 6 |(1)2 - 3(1)| = -4(1) + 6 2 = -2 so 2 not good 2 = 2 so 1 good
Ex. 8 A ski club chartered a bus for a skit trip at a cost of $480. In an attempt to lower the bus fare per skier, the club invited nonmembers to go along. After five nonmembers joined the trip, the fare per skier was decreased by $4.80. How many club members are going on the trip? (Cost per skier)(# of skiers) = cost of trip (480/x – 4.80) (x + 5) = 480 (x – 20)(x + 25) = 0 x = 20, -25 (x + 5) = 480 (480 – 4.8x)(x + 5) = 480x 480x + 2400 – 4.8x2 – 24x = 480x – 4.8x2 – 24x + 2400 = 0 x2 + 5x – 500 = 0
Compound Interest • A= future value • P = present value • r = interest rate • n = times compounded / year • t = years
Ex. 9 When you were born, your grandparents deposited $5000 in a long-term investment in which the interest was compounded quarterly. Today, on your 25th birthday, the value of the investment is $25,062.59. What is the annual interest rate for this investment?