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Question
Find the product.
`(5sqrt(7) + 3)(4 - sqrt(7))`
Sum
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Solution
Let’s find the product:
`(5sqrt(7) + 3)(4 - sqrt(7))`
1. `5sqrt(7) xx 4`
= `20sqrt(7)`
2. `5sqrt(7) xx (-sqrt(7))`
= –5 × 7
= –35
3. 3 × 4
= 12
4. `3 xx (-sqrt(7))`
= `-3sqrt(7)`
Now combine:
`20sqrt(7) - 35 + 12 - 3sqrt(7)`
Group like terms:
`20sqrt(7) - 3sqrt(7) = 17sqrt(7)`
`-35 + 12 = -23`
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