a. (3√5+2) (4√5-7)b. √320 - √405 + √80.... Question from @cherry0311

October 2022 2 9 Report

a. (3√5+2) (4√5-7)
b. √320 - √405 + √80

andreadwik99

Jawaban:

a.46-13√5

Penjelasan dengan langkah-langkah:

A.(3√5 + 2)(4√5 - 7)

= (3√5 . 4√5) + (2 . 4√5) + (-7 . 3√5) + (2 . - 7)

= 60 + 8√5 - 21√5 - 14

= 46 - 13√5

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MaulanaAlief

SOAL A.

$(3 \sqrt{5} + 2)(4 \sqrt{5} - 7)$

$= (3 \sqrt{5})(4 \sqrt{5} - 7) + (2)(4 \sqrt{5} - 7)$

$= 12 \sqrt{25} - 21 \sqrt{5} + 8 \sqrt{5} - 14$

$= 12 \times 5 - (21 - 8) \sqrt{5} - 14$

$= 60 - 14 - 13 \sqrt{5}$

$= 46 - 13 \sqrt{5}$

SOAL B.

$\sqrt{320} - \sqrt{405} + \sqrt{80}$

$= \sqrt{64 \times 5} - \sqrt{81 \times 5} + \sqrt{16 \times 5}$

$= 8 \sqrt{5} - 9 \sqrt{5} + 4 \sqrt{5}$

$= (8 - 9 + 4) \sqrt{5} = 3 \sqrt{5}$

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