Lesson 3.5 Check Your Understanding Outcome A5 page 159-165 Expand and simplify. (c + 3)(c 7) a) – (5 b) s)(9 s) – – Solutions a) (c + 3)(c 7) – Method 1 Use a rectangle diagram. (c + 3)(c 7) = + (–7c) + 3c + (–21) Combine like terms. c2 – = 4c 21 c2 – – Method 2 Use the distributive property. (c + 3)(c 7) = 7) + 3(c 7) c(c – – – = (c)(c) + (c)(–7) + (3)(c) + (3)(–7) = 7c + 3c 21 Combine like terms. c2 – – = 4c 21 c2 – – b) (5 s)(9 s) – – Use the distributive property. (5 = 5(9 + (–s)(9 s)(9 s) s) s) – – – – = (5)(9) + (5)(–s) + (–s)(9) + (–s)(–s) = 45 5s 9s + s2 – – = 45 14s + s2 –
Lesson 3.5 Check Your Understanding Outcome A5 page 159-165 Expand and simplify. a) (c + 3)(c – 7) b) (5 – s)(9 – s) Solutions a) (c + 3)(c – 7) Method 1 Use a rectangle diagram. (c + 3)(c – 7) = c2 + (–7c) + 3c + (–21) Combine like terms. = c2 – 4c – 21 Method 2 Use the distributive property. (c + 3)(c – 7) = c(c – 7) + 3(c – 7) = (c)(c) + (c)(–7) + (3)(c) + (3)(–7) = c2 – 7c + 3c – 21 Combine like terms. = c2 – 4c – 21 b) (5 – s)(9 – s) Use the distributive property. (5 – s)(9 – s) = 5(9 – s) + (–s)(9 – s) = (5)(9) + (5)(–s) + (–s)(9) + (–s)(–s) = 45 – 5s – 9s + s2 = 45 – 14s + s2
miap_ch3_notes.docx