Substituting into Algebraic Equations Graphics used are from MS clipart

Evaluate if Every time you see an “x” you replace it with (-6) and then solve. -6 + 3 =-3 Think of tiles: 6 white tiles add 3 red tiles. Take out the ones that match up and you have 3 white tiles left or -3

+ 3 – n 3 – (-6) 3 + 6 = 9 Evaluate if n = -6 Minus and a minus give you a + Rewrite the question with a single +

3p – 2q 3(8) – 2(3.5) 24 - 7 = 17 Two Substitutions Solve if p is 8 and q is 3.5 This time you must make two substitutions. Where there is a p, you substitute with an 8 and where there is a q, you substitute with 3.5 3p – 2q 3(8) – 2(3.5) 24 - 7 = 17

Now try these where: p=8 and q=3.5 p + 3q 5p – 6q 2p + 10q Check Your Answers!

Which expressions have the same value when m=4? b) 30 – 5m c) 2m + 3 d) m + 8 2 e) 21 – 2m f) 5(m+2) 3 g) 8m – 5m -1 h) 3m – m + 2 Enter the letters of the expressions that have the same value! Check Your Answers