Question

What is the solution of the equations $x-y=0.9$ and $11{(x+y)}^{-1}=2$?

• A. $x=3.2$ and $y=2.3$
• B. $x=1$ and $y=0.1$
• C. $x=2$ and $y=1.1$
• D. $x=1.2$ and $y=0.3$

Answer 1

The correct option is A $x=3.2$ and $y=2.3$

$11(x+y{)}^{-1}=2\Rightarrow 2(x+y)=\mathrm{11...}(1)$

$6x-y=0.9...\left(2\right)$

$(\frac{\left(1\right)}{2}+(2\left)\right)\Rightarrow 2x=6.4$

$\Rightarrow x=3.2:y=2.3$