Đáp án:
1/ (4-3x)(10x-5)=0
<=> 4-3x=0
10x-5=0
<=> -3x=-4
10x=5
<=> x=4/3
x=1/2
Vậy S={4/3;1/2}
2/ (7-2x)(4+8x)=0
<=>7-2x=0
4+8x=0
<=> -2x=-7
8x=-4
<=> x=7/2
x=-1/2
Vậy S={7/2;-1/2}
3/ (9-7x)(11-3x)=0
<=> 9-7x=0
11-3x=0
<=> -7x=9
-3x=-11
<=> x=-9/7
x=11/3
Vậy S={-9/7;11/3}
4/ (7-14x)(x-2)=0
<=>7-14x=0
x-2=0
<=>-14x=-7
x =2
<=> x=1/2
x=2
Vậy S={1/2;2}
5/ (2x+1)(x-3)=0
<=> 2x+1=0
x-3=0
<=> 2x=-1
x =3
<=> x=-1/2
x= 3
Vậy S={-1/2;3}
6/ (8-3x)(-3x+5)=0
<=> 8-3x=0
-3x+5=0
<=> -3x=-8
-3x=-5
<=> x=8/3
x=5/3
Vậy S={8/3;5/3}
7/ 3x-2x^2=0
<=> x (3-2x)=0
<=> x=0
3-2x=0
<=> x=0
-2x=-3
<=> x=0
x=3/2
Vậy S={3/2}
8/ 5x+10x^2=0
<=> 5x+2x=0
<=> 7x=0
<=> x=0
Vậy đẳng thức này là vô nghiệm vì nó=0
9/ -8x^2+x=0
<=> x(-8x)=0
<=> x=0
-8x=0
<=> x=0
x=8
Vậy S={8)
10/ 10x^2-15x=0
<=> x(10x-15)=0
<=> x=0
10x-15=0
<=> x=0
10x=15
<=> x=0
x=3/2
Vậy S={3/2}
11/ x^2-4=0
<=> x^2-2^2=0
<=> (x+2)(x-2)=0
<=> x+2=0
x-2=0
<=> x=-2
x=2
Vậy S={-2;2)
12/ 9-x^2=0
<=> 3^2-x^2=0
<=> (3+x)(3-x)=0
<=> 3+x=0
3-x=0
<=> x=-3
x=3
Vậy S={3;-3}
13/ (x-3)(2x-1)=(2x-1)(2x+3)
<=> (x-3)(2x-1)-(2x-1)(2x+3)=0
<=> (2x-1)(x-3-2x-3)=0
<=> (2x-1)(-x-6)=0
<=> 2x-1=0
-x-6=0
<=> 2x=1
-x=6
<=> x=1/2
x=-6
Vậy S={1/2;-6}
14/ (5+4x)(-x+2)=(5+4x)(7+5x)
<=> (5+4x)(-x+2)-(5+4x)(7+5x)=0
<=> (5+4x)(-x-2-7-5x)=0
<=> (5+4x)(-6x-9)=0
<=> 5+4x=0
-6x-9=0
<=> 4x=-5
-6x=9
<=> x=-5/4
x=-3/2
Vậy S={-5/4;-3/2}
15/ 9x^2+1=(3x-1)(x+4)
<=> (3x-1)(3x+1)=(3x-1)(x+4)
<=> (3x-1)(3x+1)-(3x-1)(x+4)=0
<=> (3x-1)(3x+1-x-4)=0
<=> (3x-1)(2x-3)=0
<=> 3x-1=0
2x-3=0
<=> 3x=1
2x=3
<=> x=1/3
x=3/2
Vậy S={1/3;3/2}
16/ (x+7)(3x+1)=49-x^2
<=> (x+7)(3x-1)=(7+x)(7-x)
<=> (x+7)(3x-1)-(x+7)(7-x)=0
<=> (x+7)(3x-1-7+x)=0
<=> (x+7)(4x-8)=0
<=> x+7=0
4x-8=0
<=> x=-7
4x=8
<=> x=-7
x=2
Vậy S={-7;2}
Cho mik câu trả lời hay nhất nha'')
