問題文全文(内容文)：
$x+y=2a$のとき
$\frac{(x-a)(y-a)}{(x-a)^2+(y-a)^2}$

慶應義塾女子高等学校

問題文全文(内容文)：
$x+y+z=7,xyz=7$
$\frac{1}{x}+\frac{1}{y}+\frac{1}{z} = \frac{13}{7}$
$(1+ \frac{1}{x})(1+ \frac{1}{y})(1+ \frac{1}{z}) = ?$

2022中央大学杉並高等学校

問題文全文(内容文)：
(41)$2xy-x-2y+1$
(42)$ab-bc+cd-da$
(43)$16-12y+3xy-x^2$
(44)$x^3y+x^2-xyz^2-z^2$
(45)$a^2+b^2+2bc+2ca+2ab$
(46)$(x+y+5)(x+2y-3)$
(47)$(x-y-2)(x-y+1)$
(48)$(2x+y+4)(3x+y-5)$
(49)$-(a-b)(b-c)(c-a)$
(50)$(a+1)(b+1)(c+1)$

問題文全文(内容文)：
Let's enjoy oriental mathematics for just a little while.
You will discover a cute world from mathematics.
Everyone in the world should love and be good at mathematics.

We are introducing the entrance exam questions for Japanese high schools.
It's an important issue for you to understand the basics of mathematics.
Would you like to solve this math problem and check out our commentary?

問題文全文(内容文)：
$x^2+\sqrt 2x = y^2+ \sqrt 2 y = 5(x \neq y)$を満たすとき
$x^2+y^2 =?$

明治大学付属明治高等学校