Question

Tentukan hasil dari (2√3–5√7)(2√3–5√7)=
pakai cara

Answer 1

solving the expression
`\left(2√(3)-5√(7)\right)\:\left(2√(3)-5√(7)\right)` we get
`\mathbf{187+20√(21)}`

Explanation:

We need to solve:
`\left(2√(3)-5√(7)\right)\:\left(2√(3)-5√(7)\right)`

We can write it as:

`\left(2√(3)-5√(7)\right)\:\left(2√(3)-5√(7)\right)\\=\left(2√(3)-5√(7)\right)^2`

We can use formula:
`a^2-b^2=a^2-2ab+b^2`

`=\left(2√(3))^2-2(2√(3))(-5√(7))+(-5√(7)\right)^2\\=4(3)+20√(3)√(7)+25(7)\\=12+20√(3* 7)+175\\=187+20√(21)`

So, solving the expression
`\left(2√(3)-5√(7)\right)\:\left(2√(3)-5√(7)\right)` we get
`\mathbf{187+20√(21)}`