Question

Evaluate , given and .
 

Answer 1

Ta có: \(a+b=8\)

\(\Rightarrow\left(a+b\right)^2=8^2\)

\(\Rightarrow a^2+2ab+b^2=64\)

\(\Rightarrow a^2+2.10+b^2=64\)

\(\Rightarrow a^2+20+b^2=64\)

\(\Rightarrow a^2+b^2=44\)

\(\left(a-b\right)^2=a^2-2ab+b^2\)

\(=\left(a^2+b^2\right)-2.10\)

\(=44-20\)

\(=24\)

Vậy \(\left(a-b\right)^2=24\)

Answer 2

(a-b)² = a²-2ab+b²

= a²+2ab+b² -4ab

⁼(a+b)²- 4ab

=8² - 4.10

=64-40

=24

thanks