# Secondary 2 Maths

## 1 Answer

\[500=(5x-5y)^2=(5x)^2+(5y)^2 -2\cdot (5 x)(5y)=25x^2+25y^2-50xy.\]

Since $xy=5$,

\[500=25x^2+25y^2-50xy=25x^2+25y^2-50\cdot 5=25x^2+25y^2-250\]

\[\Rightarrow 500+250=25x^2+25y^2\]

\[\Rightarrow 750=25(x^2+y^2)\]

\[\Rightarrow x^2+y^2=\frac{750}{25}=30.\]

Savionf

557

Join Matchmaticians Affiliate Marketing
Program to earn up to a 50% commission on every question that your affiliated users ask or answer.

- 1 Answer
- 181 views
- Pro Bono

### Related Questions

- Foreign Carnival Systems Algebra Problem
- How do you go about solving this question?
- Need to figure distance between two points/lines.
- Prove that $A - B=A\cap B^c$
- Let $z = f(x − y)$. Show that $\frac{\partial z}{\partial x}+\frac{\partial z}{\partial y}=0$
- Differentiate $f(x)=\int_{\tan x}^{0} \frac{\cos t}{1+e^t}dt$
- Calculating Speed and Velocity
- Closest Points on Two Lines: How to use algebra on equations to isolate unknowns?