=(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.