4x^2-25-(2x5-5)(2x+7)=0
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mình sửa đề chút nha!
4x^2 - 25 - (2x - 5)(2x + 7) = 0
<=>(2x - 5)(2x + 5) - (2x - 5)(2x + 7) = 0
<=>(2x - 5)(2x + 5 - 2x -7) = 0
<=> -2(2x - 5) = 0
<=> -4x + 10 = 0
<=> -4x = -10
<=> x = 5/2
![](https://rs.olm.vn/images/avt/0.png?1311)
câu1
(3x-1).(1/2x5)=0
=>3x-1=0 hoặc 1/2x5=0
=>x=1/3 =>x=0
câu2
1/4+1/3 :(2x-1)=5
=> 1/3:(2x-1)=19/4
=>2x-1 =57/4
=>2x=61/4
=>x=61/8
còn hai câu sau bn ghi đề mik ko hỉu
1.
a)(3x-1)(1/2x5)=0
=>3x-1=0 hoặc 1/2x5=0
3x=0+1 x=0:1/2:5
x=1/3 x=0
Vậy x=1/3 hoặc x=0
b)1/4+1/3:(2x-1)=5
1/3:(2x-1)=5-1/4=20/4-1/4=19/4
2x-1=1/3:19/4=1/3*4/19=4/57
2x=4/57+1=4/57+57/57=61/57
x=61/57:2=61/57*1/2=61/114
Vậy x=61/114
c)(2x+2/5)2-9/25=0=02-9/25
=>2x+2/5=0
2x=0-2/5
x=-2/5:2=-2/5*1/2
x=-1/5
Vậy x=-1/5
d)(3x-1/2)3+1/9=0=03+1/9
=>3x-1/2=0
3x=0+1/2
x=1/2:3=1/2*1/3
x=1/6
Vậy x=1/6
![](https://rs.olm.vn/images/avt/0.png?1311)
4x^2-25-(2x-5)(2x+7)=0
<=> 4x^2 - 25 - (4x^2 + 14x - 10x - 35) = 0
<=> 4x^2 - 25 - 4x^2 - 14x + 10x + 35 = 0
<=> -4x + 10 = 0
<=> x = -10/-4
<=> x = 5/2
![](https://rs.olm.vn/images/avt/0.png?1311)
\(4x^2-25-\left(2x-5\right)\left(2x+7\right)=0\\ \Leftrightarrow4x^2-25-\left(4x^2+14x-10x-35\right)=0\\ \Leftrightarrow4x^2-25-4x^2-14x+10x+35=0\\
\Leftrightarrow-4x+10=0\)
\(\Leftrightarrow x=\frac{-10}{-4}\\
\Leftrightarrow x=\frac{5}{2}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Suy ra (2x-4)-(3x-3×5)=1 Suy ra(2x-4)-3x+15=1 Suy ra 2x-4-3x+15=1 Suy ra (2x-3x)+(15-4)=1 -1x+11=1 1-11=-1x -1x=-10 X=10
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(5x-2\right)\left(2x+7\right)-4x^2-25=0\)
\(10x+35-4x^2-14x-4x^2+25=0\)
\(-4x+60-8x^2=0\)
\(-4\left(2x^2+x-15\right)=0\)
\(-4\left(2x^2+6x-5x-15\right)=0\)
\(-4\left(2x-5\right)\left(x+3\right)=0\)
=> \(x\) ∈ \(\left\{\dfrac{5}{2};-3\right\}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
8x2+30x+7=0
8x2+16x+14x+7=0
8x(x+2) +7(x+2)=0
(8x+7)(x+2)=0
=>\(\orbr{\begin{cases}8x+7=0\\x+2=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-\frac{7}{8}\\x=-2\end{cases}}}\)
4x2 - 25 - 5(2x + 7 ) = 0
=> 4x2 - 25 - 10x - 35 = 0
=> 4x2 - 10x - 60 = 0
đến dố bạn tự giải nốt nha sử dụng pt hoặc tính dấy là ra
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