Question 13 - Identify and correct errors in the sentences - Chapter 12 Class 8 Factorisation

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Ex 14.4, 13 - Find and correct (2a + 3b) (a - b) = 2a^2 - 3b^2

Ex 14.4, 13 - Chapter 14 Class 8 Factorisation - Part 2

Transcript

Question 13 Find and correct the errors in the following mathematical statements. (2a + 3b) (a – b) = 2𝑎^2 – 3𝑏^2 (2a + 3b) (a – b) = 2𝑎^2 – 3𝑏^2 Solving L.H.S : (2a + 3b) (a – b) = 2a (a − b) + 3b (a − b) = (2a × a) − (2a × b) + (3b × a) − (3b × b) = 〖2𝑎〗^2 − 2ab + 3ba − 〖3𝑏〗^2 = 〖2𝑎〗^2 − 2ab + 3ab − 〖3𝑏〗^2 Taking ab common = 〖2𝑎〗^2 + ab (−2 + 3) − 〖3𝑏〗^2 (Since 3ba = 3ab) = 〖2𝑎〗^2 + ab − 〖3𝑏〗^2 ∴ (2a + 3b) (a − b) = 〖𝟐𝒂〗^𝟐 + ab − 〖𝟑𝒃〗^𝟐 is the correct statement

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