解方程5y-y的二次方=4

5y-y2次=4
0=y2次-5y+4
0=(y-4)(y-1)
y=4 or 1

0=y2次-5y+4
0=(y-4)(y-1)
y=4 or 1

5y-y的二次方=4
5y-y(5y-y)=4
4y(4y)=4
4y^2=4
y^2=1
y=1

(5y-2)^2=4
25Y^2-10Y+4=4
25y^2-10y=0
y(25y-10)=0
y=0 or 25y-10=0
or 25Y=10
or y=10/25>>>2/5

(5y-y)2次=4
5y-y=2
4y=2
y=0.5
緊記係括號5y-y,唔係你好易計左5y-y二次,咁就永遠都計唔到

5y-y^2=4
-y^2+5y-4=0
y^2-5y+4=0
(y-4)(y-1)=0

所以，y=4,1

5y-y^2=4
y^2-5y+4=0
(y-1)(y-4)=0
y=1 or y=4