a) Ta có: 4(x-5)+6(x-7)=0
⇔4x-20+6x-42=0
⇔10x-62=0
⇔10x=62
⇔\(x=\frac{31}{5}\)
Vậy: \(x=\frac{31}{5}\)
b) Ta có: 3(2x-7)-4(2x+3)=0
⇔6x-21-8x-12=0
⇔-2x-33=0
⇔-2x=33
⇔\(x=-\frac{33}{2}\)
Vậy: \(x=-\frac{33}{2}\)
Bài 3: Tìm x
1) ( x + 5)2 = (x + 3)( x – 7)
2) (x + 2)(x2 -2x + 4) = 15 + x(x2 +2)
3) x2 + 6x = -9
4) x3 - 9x2 = 27 – 27x
5) (2x + 1)2 - 4(x + 2)2 = 9
6) –x2 - 2x +15 = 0
Tìm x:
a) (x-20) mũ 2 -(x+1)(x+3)=-7
b) (3x+5)(4-3x)=0
c) x mũ 3 -9x=0
d)2/3x (x mũ 2 -4)=0
e) (2x+1)-x(2x+1)=0
f)(2x-1) mũ 2 -(2x+5) (2x-5) =18
g)x mũ 2 -25 =6x-9
bài 3 tìm x
a)(2x+3)^2-(2x+1)(2x-1)=32
b)(4x+3)(4x-3)-(4x-5)^2=46
c)(x+4)^2+(x+3)(x-3)-5(x+1)(x-1)=16
d)92x-1)^2+(x+3^2-5(x+7)(x-7)=0
e)25x^2-9=0
tìm x
a,(2x+3) 2-(2x+1)(2x-1)=22
b,(2x-1) 3 -4x2 (2x-3)=5
c,(x-3)2-4=0
d,(2x-1)2+(x+3)2-5(x+7)(x-7)=0
bài 2 tìm giá trị nhỏ nhất
A=x2+20x+9
B=4x2+5x+7
a) x2(x - 5) + 5 - x = 0; b) 3x4 - 9x3 = -9x2 + 27x;
c) x2(x + 8) + x2 = -8x; d) (x + 3)(x2 -3x + 5) = x2 + 3x.
e) 3x(x - 1) + x - 1 = 0;
f) (x - 2)(x2 + 2x + 7) + 2(x2 - 4) - 5(x - 2) = 0;
g) (2x - 1)2 - 25 = 0;
h) x3 + 27 + (x + 3)(x - 9) = 0.
i)8x3 - 50x = 0; k) 2(x + 3)-x2 - 3x = 0;
m)6x2 - 15x - (2x - 5)(2x + 5) =
Tìm x biết
a, 5x (x - 1) - (1 - x) = 0
b, (x - 3)2 - (2x + 3)2 = 0
c, 2x (x2 - 4) = 0
d, (x - 2)2 - (x - 2) (x + 3) = 6
e, x2 + 6x - 7 = 0
Giai pt : a, 3x+18=0
B, 6x-7=3x+2
C, 2x/x+3+4(x-3)/x =6
Bài 3
1.(x-1)(x+2)+5x-5=0
2.(3x+5)(x-3)-6x-10=0
3.(x-2)(2x+3)-7x2+14x=0
4.(x+1)(x-3)-15+5x=0
5.5(2x-1)(x+3)+5x-10x2=0
Bài4
1.3x-6+(x+1)(x-2)=0
2.4x2+6x-(2x+3)(3x-x)=0
3.5x-10-(2-x)(4+x)=0
4.10-10x+(x-1)(x-3)=0
5.20x2+30x-2(x-5)(2x+3)=0
Đề: Tìm x
a)2x.(3x+5)-x.(6x-1)=33 k)5(x+3)-2x(x+3)=0
b)x(3x-1)+12x-4=0 i)5x(x-2)-(2-x)=0
c)5x(2x+1)-12x-6=0 m)x(x-1)-2(1-x)=0
d)x3-5x2+4x-20=0
e)2x3-5x2+2x-5=0
g)(x-2)3-x(x+1).(x-1)+62=5
