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a: Ta có: \(x^2+3x-10=0\)
\(\Leftrightarrow\left(x+5\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=2\end{matrix}\right.\)
b: Ta có: \(x^2-5x-6=0\)
\(\Leftrightarrow\left(x-6\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-1\end{matrix}\right.\)
20) -5-(x + 3) = 2 - 5x ⇔ -5 - x - 3 = 2 -5x ⇔ 4x = 10 ⇔ x = \(\frac{5}{2}\)
Vậy...
Mấy cái này chuyển vế đổi dấu là xong í mà :3
1,
16-8x=0
=>16=8x
=>x=16/8=2
2,
7x+14=0
=>7x=-14
=>x=-2
3,
5-2x=0
=>5=2x
=>x=5/2
Mk làm 3 cau làm mẫu thôi
Lúc đăng đừng đăng như v :>
chi ra khỏi ngt nản
từ câu 1 đến câu 8 cs thể làm rất dễ,bn tham khảo bài của bn muwaa r làm những câu cn lại
a) x(x - 1) = 0
=> \(\left[\begin{array}{nghiempt}x=0\\x-1=0\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=0\\x=1\end{array}\right.\)
b) 3x2 - 6x = 0
=> 3x.(x - 2) = 0
=> x.(x - 2) = 0
=> \(\left[\begin{array}{nghiempt}x=0\\x-2=0\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=0\\x=2\end{array}\right.\)
c) x(x - 6) + 10(x - 6) = 0
=> (x - 6)(x + 10) = 0
=> \(\left[\begin{array}{nghiempt}x-6=0\\x+10=0\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=6\\x=-10\end{array}\right.\)
d) x3 - x = 0
=> x.(x2 - 1) = 0
=> x.(x - 1).(x + 1) = 0
=> \(\left[\begin{array}{nghiempt}x=0\\x-1=0\\x+1=0\end{array}\right.\)=> \(\left[\begin{array}{nghiempt}x=0\\x=1\\x=-1\end{array}\right.\)
a)
\(x\left(x-1\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x-1=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=1\end{array}\right.\)
Vậy x=0 ; x =1
b)
\(3x^2-6x=0\)
\(\Rightarrow3x\left(x-2\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x-2=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=2\end{array}\right.\)
Vậy x=0 ; x =2
c)
\(x\left(x-6\right)+10\left(x-6\right)=0\)
\(\Rightarrow\left(x-6\right)\left(x+10\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x-6=0\\x+10=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=6\\x=-10\end{array}\right.\)
Vậy x=6 ; x = -10
d)
\(x^3-x=0\)
\(\Rightarrow x\left(x^2-1\right)=0\)
\(\Rightarrow x\left(x-1\right)\left(x+1\right)=0\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x-1=0\\x+1=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=0\\x=1\\x=-1\end{array}\right.\)
Vậy x = 0 ; x = 1 ; x= - 1
\(1,\)
\(2x\left(x-3\right)-\left(3-x\right)=0\)
\(\Leftrightarrow2x\left(x-3\right)+\left(x-3\right)=0\)
\(\Leftrightarrow\left(2x+1\right)\left(x-3\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}2x+1=0\\x-3=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{-1}{2}\\x=3\end{cases}}\)
\(2,\)
\(3x\left(x+5\right)-6\left(x+5\right)=0\)
\(\Leftrightarrow\left(3x-6\right)\left(x+5\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}3x-6=0\\x+5=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-5\end{cases}}\)
\(3,\)
\(x^4-x^2=0\)
\(\Leftrightarrow x^2\left(x^2-1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x^2=0\\x^2-1=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=\pm1\end{cases}}\)
\(4,\)
\(x^2-2x=0\)
\(\Leftrightarrow x\left(x-2\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)
\(5,\)
\(x\left(x+6\right)-10\left(x-6\right)=0\)
\(\Leftrightarrow x^2+6x-10x+60=0\)
\(\Leftrightarrow x^2-4x+60=0\)
\(\Leftrightarrow x^2-4x+4+56=0\)
\(\Leftrightarrow\left(x-2\right)^2=-56\)(Vô lý)
=> Phương trình vô nghiệm
1.
<=> \(\left[{}\begin{matrix}4-3x=0\\10-5x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{4}{3}\\x=2\end{matrix}\right.\)
2.
<=>\(\left[{}\begin{matrix}7-2x=0\\4+8x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=-\dfrac{1}{2}\end{matrix}\right.\)
3.
<=>\(\left[{}\begin{matrix}9-7x=0\\11-3x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{7}\\x=\dfrac{11}{3}\end{matrix}\right.\)
4.
<=>\(\left[{}\begin{matrix}7-14x=0\\x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=2\end{matrix}\right.\)
5.
<=>\(\left[{}\begin{matrix}\dfrac{7}{8}-2x=0\\3x+\dfrac{1}{3}=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{16}\\x=-\dfrac{1}{9}\end{matrix}\right.\)
6,7. ko đủ điều kiện tìm
a) Ta có: \(\left(2x+1\right)^2-\left(3x-4\right)^2=0\)
\(\Leftrightarrow\left(2x+1-3x+4\right)\left(2x+1+3x-4\right)=0\)
\(\Leftrightarrow\left(5-x\right)\left(5x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=\dfrac{3}{5}\end{matrix}\right.\)
b) Ta có: \(5x^3-3x^2+10x-6=0\)
\(\Leftrightarrow x^2\left(5x-3\right)+2\left(5x-3\right)=0\)
\(\Leftrightarrow5x-3=0\)
hay \(x=\dfrac{3}{5}\)
\(2x\left(3x-6\right)-10\left(6-3x\right)=0\)
\(\Leftrightarrow2x\left(3x-6\right)+10\left(3x-6\right)=0\)
\(\Leftrightarrow\left(3x-6\right)\left(2x+10\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}3x-6=0\\2x+10=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}3x=6\\2x=-10\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-5\end{cases}}\)
Vậy x=2 hoặc x=-5
Trả lời:
\(2x\left(3x-6\right)-10\left(6-3x\right)=0\)
\(\Leftrightarrow2x\left(3x-6\right)+10\left(3x-6\right)=0\)
\(\Leftrightarrow\left(2x+10\right)\left(3x-6\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}2x+10=0\\3x-6=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x=-10\\3x=6\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=-5\\x=2\end{cases}}\)
Vậy x = - 5; x = 2 là nghiệm của pt.