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Surds question help!

(2√5+3√6)^2= (2√5+3√6)(2√5+3√6)
= (2√5)^2+2x(2√5)x(3√6)+(3√6)^2
= (2^2x√5^2)+(2x2x3x√5x√6)+(3^2x√6^2)
= 20+12√30+54
= 74+12√30

Can somebody please explain these stages to me?
Its just like expanding a quadratic.

(2√5 + 3√6)^2 = (2√5 + 3√6)*(2√5 + 3√6)
then you expand that.
(2√5)(2√5) + (2√5)(3√6) + (2√5)(3√6) + (3√6)(3√6)
simplify everything

4((√5)^2) + 12(√5)(√6) + 9((√6)^2)
4(5) + 12√5√6 + 9(6)
20 + 12√5√6 +54

because √a * √b = √ab √5√6 = √(5*6) = √30

20 + 12√30 +54 = 74 + 12√30
(edited 7 years ago)

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