a, (3 - x) = (3 - x)2
Suy ra 3-x = 1 hoặc 3-x = 0
--Nếu 3-x = 1
x = 3-1
x = 2
--Nếu 3-x = 0
x = 3 - 0
x = 3
Vậy x=2; x=3
b, x3 - 0,25x = 0
x.(x2 - 0,25) = 0
Suy ra x = 0 hoặc x2 - 0,25 = 0
x2 = 0 + 0,25
x2 = 0,25
x2 = (0,5)2
Suy ra x = 0,5
Vậy x = 0; x = 0,5
c, x2 - 10x = -25
x.(2 - 10) = -25
x.(-8) = -25
x = -25 : (-8)
x = 25/8
Vậy x = 25/8
Chúc bạn học tốt
a/ \(3-x=\left(3-x\right)^2\)
<=> \(0=\left(3-x\right)^2-\left(3-x\right)\)
<=> \(\left(3-x\right)\left(3-x-1\right)=0\)
<=> \(\left(3-x\right)\left(2-x\right)=0\)
<=> \(\orbr{\begin{cases}3-x=0\\2-x=0\end{cases}}\)<=> \(\orbr{\begin{cases}x=3\\x=2\end{cases}}\)
b/ \(x^3-0,25x=0\)
<=> \(x\left(x^2-0,25\right)=0\)
<=> \(x\left[x^2-\left(\frac{1}{2}\right)^2\right]=0\)
<=> \(x\left(x-\frac{1}{2}\right)\left(x+\frac{1}{2}\right)=0\)
<=> x = 0 hoặc \(\orbr{\begin{cases}x-\frac{1}{2}=0\\x+\frac{1}{2}=0\end{cases}}\)<=> \(\orbr{\begin{cases}x=0\\x=\pm\frac{1}{2}\end{cases}}\)
c/ \(x^2-10x=-25\)
<=> \(x^2-10x+25=0\)
<=> \(\left(x-5\right)^2=0\)
<=> \(x-5=0\)
<=> \(x=5\)