Algebraic thinking Math 123

Warm-up Solve the following equations: 2a - 13 = 15a 3b – 8 = 4b – 4c = 15

Group work A convenience store advertised two phone cards. Which one would you buy? Why? –Card 1: 3.9 cents a minute with 37 cent connection charge for each call. –Card 2: 7.9 cents a minute with no connection charge.

Group work There is a functional relationship between the frequency of cricket chirps and the temperature. To find the temperature, the rule is to count the number of chirps in one minute, divide by 4, and add 40. –What temperature does 50 chirps correspond to? –Without calculating, determine whether 100 chrips per minute will correspond to twice the temperature of 50 chirps per minute. Explain. –Translate the rule into an equation.