Solving Equations Using Algebra

6.2 in Textbookpp. 327 – 332

Investigate

Asuka invites some friends over for a party to watch the Superbowl!

• Her mom has some veggie burgers, but she doesn’t have enough. Asuka’s mom tells her that she needs twice as many veggie burgers, plus 5 more. Her mom leaves to run errands, and Asuka forgets to ask how many veggie burgers her mom has.

• There will be 33 people at the party – Asuka and 32 friends. Asuka needs to find out how many veggie burgers her mom now has.

• Check out the diagram on p. 327. • What does n represent?• Write an equation for the balance scales

model. • How many different ways can you solve the

equation?• Show each way. • Work with a partner.

Methods:

– Inspection: I know that 25 + 5 = 33, so 2n must equal 28. Since 2 x 14 = 28, n = 14.

– Guess and check: I tried n = 10, but that was too low. So I tried n = 15, and that was a little high. So I tried n = 14 and it was right.

– Algebra tiles– Balance-scales model– Short cut – algebra!

Jot down the notes that are underlined.

• We can solve an equation using algebra.• To help us visualize the equation, we think

about a model, such as balance-scales or algebra tiles.

• To solve an equation, we need to isolate the variable on one side of the equation.

• To do this, we get rid of the numbers on that side of the equation.

• When we solve an equation using algebra, WE MUST PRESERVE THE EQUALITY!

Golden Rule of Algebra:

Whatever we do to one side of the equation, we must do to the other side, too.

• And now your favourite part…. ….homework!

p. 330- 332 **due Tuesday, April 6** # 3, 5 (use tiles, choose 3), 6, 7 (choose 2), 8, 9, 12Extra challenge: #13, 14, 15