=(4x？ - 1/4 y？ )-(4x？ +y？ -4xy)

=4xy-5/4 y？

Bring x and y values into

Original formula =4*( 1/4)*(- 1)

= - 1

Step 2 tidy up first

xy-5x-xy+2y = 12； 12xy-2x+8y-8xy = 4xy+ 12

Continue to organize

2y-5x = 12①； 4y-x=6②

So the equation is easier to find.

Continue to arrange ② until x=4y-6③.

Bring ③ into ①

2y-5(4y-6)= 12

2y-20y+30= 12

y= 1

So x=4y-6=-2.

The power of 100 3 and the power of 2 = 25 (the power of 4 of 2).

75th power of 3 = 25th power of 3 (3rd power of 3).

So comparing the100th power of 2 and the 75th power of 3 is the size of comparing the 4th power of 2 and the 3rd power of 3.

2 to the fourth power =2*2*2*2= 16.

Cubic of 3 =3*3*3=27

So the fourth power of 2 < the third power of 3.

So 100 is 2 < 3 to the 75th power.