Ex.14.3 Q18 Factorization - NCERT Maths Class 8

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Question

Q18. Find and correct the errors in the statement:

\[\left( {a - 4} \right)\left( {a - 2} \right) = {a^2} - 8\]

Text Solution

What is known?

Incorrect mathematical statement.

What is unknown?

Correct mathematical statement.

Reasoning:

Solve \(L.H.S.\)

Steps:

\[\begin{align}L.H.S. &= (a - 4)(a - 2) = a \times a + \left( { - 2} \right) \times a + \left( { - 4} \right) \times a + \left[ {( - 4) \times ( - 2)} \right]\\&= {a^2} - 2a - 4a + 8\\&= {a^2} - 6a + 8\\L.H.S. &\ne R.H.S.\end{align}\]

The correct statement is \(\left( {a - 4} \right)\left( {a - 2} \right) = {a^2} - 6a + 8\)