Thursday November 12, 2009 Welcome to Algebra 1B!

Warm – Up Check Homework 4-4B Notes Assignment: 4-4B Worksheet

Solve these two systems by graphing.

I CAN... ~solve systems of equations with substitution.

2(2 – y) + 2y = 8 This is FALSE so that means…….? No solution (parallel lines) 4 – 2y + 2y = 8 4 = 8

Hint: Get c by itself. c – 4d = 1 +4d +4d c = 4d + 1 2(4d + 1) – 8d = 2 8d + 2 – 8d = = 2 This is TRUE so that means…….? Infinitely many = Same line

TRUE: such as –5 = –5False: such as 5 = 8 Solution: ____________Solution: ____________ Type of line: ___________Type of line: _________ If your variables “cancel out” and the result is: Infinitely many SAME line No solutions Parallel

Solution: (2, 6) y = x + 4 3x + 2(x + 4) = 18 3x + 2x + 8 = 18 5x + 8 = 18 5x = 10 x = 2 y = y = 6

4x + 2(–2x + 3) = 6 4x – 4x + 6 = 6 6 = 6 This is TRUE so that means…….? Infinitely many = Same line

Sue had two tests on Monday (history and biology). Her biology score was 12 points higher than her history score. The total of her two scores was 154. What was her biology test score? b = 12 + h b + h = h + h = h = 154 –12 2h = 142 h = 71 b = b = 83

Dan bought two new games for his Wii. Super Mario Brothers cost twice as much as Lego Star Wars. The total for both games was $72. What does Lego Star Wars cost? m = 2L m + L = 72 2L+ L = 72 3L = 72 L = 24

Lucy is selling girl scout cookies. She sells 4 times as many boxes of Caramel Delites as Thin Mints. Caramel Delites cost $4 per box and Thin Mints cost $3.50 per box. She makes a total of $156. How many boxes of Caramel Delites did she sell? c = 4m 4c m = 156 4(4m) m = m = 156 m = 8 c = 4(8) c = 32 16m m = 156

What does an infinitely many solutions mean? What does a no solution mean?

4-4B Worksheet