How do you multiply $(5 + 3sqrt7) (-4+5rsqrt7)$ ?

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Answer 1 · 2018-05-20T15:56:20

$color(indigo)(=> 5r (5 sqrt7 + 21) - 4(5 + 3 sqrt7)$

$(5+3 sqrt7) (-4+ 5r sqrt7)$

$=> -20 - 12 sqrt7 + 25 r sqrt7 + 15 r *7$ , removing brackets and multiplying terms

$=> -20 - 12 sqrt7 + 25 sqrt7 r + 105r$

$color(indigo)(=> 5r (5 sqrt7 + 21) - 4(5 + 3 sqrt7)$

How do you multiply (5 + 3sqrt7) (-4+5rsqrt7) (5 + 3sqrt7) (-4+5rsqrt7) ?