If someone could walk me through this with the working out included, it would be greatly appreciated. Thanks!
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Multiply the numerator and denominator by the conjugate of the denominator. The conjugate of √5 - √2 is √5 + √2 (just take the minus sign and make it positive), so multiplying the numerator and denominator by √5 + √2 gives:
(√5 - 3√2)/(√5 - √2) = [(√5 - 3√2)(√5 + √2)]/[(√5 + √2)(√5 - √2)]
= [(√5 - 3√2)(√5 + √2)]/[(√5)^2 - (√2)^2], via difference of squares
= [(√5 - 3√2)(√5 + √2)]/(5 - 2)
= [(√5 - 3√2)(√5 + √2)]/3
= (√5√5 + √2√5 - 3√2√5 - 3√2√2)/3, by FOILing the numerator
= [5 + √10 - 3√10 - 3(2)]/3
= (-1 - 2√10)/3.
I hope this helps!
(√5 - 3√2)/(√5 - √2) = [(√5 - 3√2)(√5 + √2)]/[(√5 + √2)(√5 - √2)]
= [(√5 - 3√2)(√5 + √2)]/[(√5)^2 - (√2)^2], via difference of squares
= [(√5 - 3√2)(√5 + √2)]/(5 - 2)
= [(√5 - 3√2)(√5 + √2)]/3
= (√5√5 + √2√5 - 3√2√5 - 3√2√2)/3, by FOILing the numerator
= [5 + √10 - 3√10 - 3(2)]/3
= (-1 - 2√10)/3.
I hope this helps!
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Multiply the numerator and denominator by sqrt(5) + sqrt(2) because:
(a - b) * (a + b) = a^2 - b^2
((sqrt(5) - 3 * sqrt(2)) * (sqrt(5) + sqrt(2))) / ((sqrt(5) - sqrt(2)) * (sqrt(5) + sqrt(2))) =>
(sqrt(5) * sqrt(5) - 3 * sqrt(2) * sqrt(5) + sqrt(5) * sqrt(2) - 3 * sqrt(2) * sqrt(2)) / (5 - 2) =>
(5 - 3 * sqrt(10) + sqrt(10) - 3 * 2) / 3 =>
(5 - 6 - 2 * sqrt(10)) / 3 =>
(-1 - 2 * sqrt(10)) / 3
There you go.
(a - b) * (a + b) = a^2 - b^2
((sqrt(5) - 3 * sqrt(2)) * (sqrt(5) + sqrt(2))) / ((sqrt(5) - sqrt(2)) * (sqrt(5) + sqrt(2))) =>
(sqrt(5) * sqrt(5) - 3 * sqrt(2) * sqrt(5) + sqrt(5) * sqrt(2) - 3 * sqrt(2) * sqrt(2)) / (5 - 2) =>
(5 - 3 * sqrt(10) + sqrt(10) - 3 * 2) / 3 =>
(5 - 6 - 2 * sqrt(10)) / 3 =>
(-1 - 2 * sqrt(10)) / 3
There you go.