By Jeffrey Bivin Lake Zurich High School jeff
By: Jeffrey Bivin Lake Zurich High School jeff. bivin@lz 95. org Last Updated: October 11, 2005
y = 3 x + 5 2 x + 4 y = 34 2 x + 4(3 x + 5) = 34 y = 3(1) + 5 2 x + 12 x + 20 = 34 14 x + 20 = 34 y=3+5 y=8 14 x = 14 x = 1 Jeff Bivin -- LZHS
3 x – 5 y = 14 2 x + 4 y = -20 I think I’ll choose to eliminate the y variable. Decide which variable you want to eliminate. Jeff Bivin -- LZHS
3 x – 5 y = 14 2 x + 4 y = -20 12 x - 20 y = 56 3(-2) – 5 y = 14 10 x + 20 y = -100 -6 - 5 y = 14 -5 y = 20 y = -4 22 x Jeff Bivin -- LZHS = -44 x = -2
2 x + 7 y = 48 3 x + 5 y = 28 I think I’ll choose to eliminate the x variable. Decide which variable you want to eliminate. Jeff Bivin -- LZHS
2 x + 7 y = 48 3 x + 5 y = 28 6 x + 21 y = 144 3 x + 5(8) = 28 -6 x - 10 y = -56 3 x + 40 = 28 3 x = -12 x = -4 11 y = 88 y = 8 Jeff Bivin -- LZHS
4 x + 3 y = -19 6 x + 5 y = -32 I think I’ll choose to eliminate the x variable. Decide which variable you want to eliminate. Jeff Bivin -- LZHS
4 x + 3 y = -19 6 x + 5 y = -32 12 x + 9 y = -57 6 x + 5(-7) = -32 -12 x - 10 y = 64 6 x - 35 = -32 6 x = 3 -y = 7 y = -7 Jeff Bivin -- LZHS
y = -2 x - 6 6 x + 3 y = 11 6 x + 3(-2 x - 6) = 11 6 x - 18 = 11 - 36 = 11 Jeff Bivin -- LZHS
x = 5 y + 1 2 x - 10 y = 2 2(5 y + 1) - 10 y = 2 10 y + 2 - 10 y = 2 2= 2 Jeff Bivin -- LZHS
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