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Expanding brackets and substitution

Expanding brackets and substitution. Slideshow 8, Room 307 Mathematics, Mr Richard Sasaki. Objectives. Recall how to substitute into expressions Practice expanding brackets Expand brackets before substituting into expressions. Substitution.

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Expanding brackets and substitution

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  1. Expanding brackets and substitution Slideshow 8, Room 307Mathematics, Mr Richard Sasaki

  2. Objectives • Recall how to substitute into expressions • Practice expanding brackets • Expand brackets before substituting into expressions

  3. Substitution To substitute, we swap algebraic symbols for numbers so we can get a numeric answer. Example Calculate when and . Try the short worksheet. = = Usual algebraic rules for expressions apply.

  4. Substitution Answers 9 2 56 144 75 32 8.5 67 830 Yen 12 4 = (-3) + 2 + + (-2) + (-27) + (-2.5) = -32 – + = -32 8

  5. Expanding brackets To substitute numbers into expressions with brackets, it can be easier to expand them first. This lesson, we will expand each expression before substituting.

  6. Expanding brackets Example Simplify and substitute and into it. = 32+24 = That’s about it, try the last worksheets! 56 =

  7. Answers 18 36 6 72 1 510 (256 + 128 + 64 + 32 + 16 + 8 + 4 + 2) 8 -24

  8. One last example. Example For , simplify and substitute for and . Let’s try with substitution first. (1 + 2)2 = 9 How about expanding first? ? Mmm… 12 + 22 = 5 Well that didn’t work. . So what is it?

  9. Let’s look at (x + y)2 as an area. Here we want the total area. I made the size of look different to but this doesn’t matter.

  10. So if we add each part together we get… = = How about ? And how about ?

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