← Unit 2: Algebra Mathematics · Grade 9 ← Prev3 / 85Next →
Communication and Collaboration

Expressions and matrices narration

Expressions and matrices narration

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Transcript

[0:00] An algebraic expression uses letters to stand for unknown numbers, joined by plus, minus, times and divide. [0:40] Like terms have the same letters and powers, so we can combine 3x and 5x into 8x, but not 3x and 5y. [1:25] Factorising reverses expansion; we pull out a common factor, so 6x plus 9 becomes 3 times the bracket 2x plus 3. [2:10] A matrix is a rectangular arrangement of numbers in rows and columns, useful for storing tables of data. [2:55] We add matrices of the same size by adding matching entries, and scale a matrix by multiplying every entry.

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