Question

How to multiply rational expressions?
pls help me...

Answer 1

Point :

A × B = B × A

Ex)

`(1)/(2) * (3)/(4) = (3)/(4) * (1)/(2) = (3)/(2) * (1)/(4)`

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a )

`\frac{12 {a}^(2) }{25 {b}^(3) } * \frac{5b}{4 {a}^(4) } = \frac{12 {a}^(2) }{4 {a}^(4) } * \frac{5b}{25 {b}^(3) } = \\`

`\frac{4 {a}^(2) * 3 }{4 {a}^(2) * {a}^(2) } * \frac{5b}{5b * 5 {b}^(2) } = \\`

`\frac{3}{ {a}^(2) } * \frac{1}{5 {b}^(2) } = \frac{3}{5 {a}^(2) {b}^(2) } \\`

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b )

`\frac{ {x}^(2) - 2x - 15 }{ {x}^(2) - 9 } * \frac{ {x}^(2 ) - 6x + 9 }{4x - 12} = \\`

`((x - 5)(x + 3))/((x - 3)(x + 3)) * ((x - 3)(x - 3) )/(4(x - 3)) = \\`

`((x - 5))/((x - 3)) * ((x - 3))/(4) = \\`

`((x - 3)(x - 5))/((x - 3) \: \: \: * \: \: 4) = (x - 5)/(4) \\`

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And we're done.....♥️♥️♥️♥️♥️