Question

Factorise x²-5 please

Answer 1

`\sf \: {x}^(2) - 5`

`\sf \: Use \: the \: algebraic \: identity \\ \sf \: a {}^(2) - {b}^(2) = (a - b)(a + b)`

`\sf \: Substitute \: the \: value \: of \: a \: and \: b \: in \: the \: identity.`

`\sf \: a = \sqrt{x ^(2) } = x \\ \sf \: b = √(5)`

`\sf \: the \: identity \: becomes \:`

`\sf {x}^(2) - 5 \\ \sf = (x - √(5) )(x + √(5) ) \\`

Answer ⟶
`\boxed{\bf{(x - √(5) )(x + √(5) )}}`