Week 9 – Math 10

This week I learnt how to use an area model to expand an expression. It’s very useful since it organizes everything so you don’t miss a step while multiplying terms. Heres an example:

(x - 4)(x^2 - 6x + 3)

Draw a lowercase T and divide the bottom and right according to the number of terms in the expression. Since a binomial is being multiplied by a trinomial, the top is divided in two and the sides are divided in three.

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Now plug the numbers into their corresponding spots:

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Then, you simply multiply the numbers together! You can almost think of it like playing battleship:

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I have colour coded all the like terms together. The ones that are the same colour are added together, and the final answer is x^3 - 10x^2 + 27x - 12 .

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Week 8 – Math 10

This week, I got half of the question correct, since my final answer was 1 + 9b^2 . However, the actual answer was 1 + 6b + 9b^2 and I could not figure out why. While I was going over the homework with my friends and discussing this one question, the solution suddenly popped into my head and the question finally made sense!

I had been adding and multiplying the exponents together, but that was only half the battle:

(1^2 + 3^2b^2) = 1 + 3b^2

But the exponent meant that the binomial is multiplying by itself, so using distribution to solve the problem is the correct way to do it:

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(1 + 3b)\cdot (1 + 3b) = 1 + 6b + 9b^2

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