a) (2x+3)(x-4)+(x-5)(x-2)=(3x-5)(x-4)
b)(8x-3)(3x+2)-(4x+7)(x+4)=(2x+1)(5x-1)
c)(\(^{x^2}\)-5)(x+2)+5x=2\(^{x^2}\)+17
d)(\(^{x^2}\)-x+1)(x+1)-\(x^3\)+3x=15
Tìm x biết :
a, 4.(18 - 5x) - 12.(3x - 7) = 15.(2x - 16) - 6(x + 14)
b, 5.(3x + 5) - 4.(2x - 3) = 5x + 3.(2x + 12) + 1
c, 2.(5x - 8) - 3.(4x - 5) = 4.(3x - 4) + 11
d, (3x + 2)(2x + 9) - (x + 2)(6x + 1) = (x + 1) - (x - 6)
e, (8x - 3)(3x + 2) - (4x + 7)(x + 4)= (2x + 1)(5x - 1) - 33
Noob ơi, bạn phải đưa vào máy tính ý solve cái là ra x luôn, chỉ tội là đợi hơi lâu
a, 4.(18 - 5x) - 12(3x - 7) = 15(2x - 16) - 6(x + 14)
=> 72 - 20x - 36x + 84 = 30x - 240 - 6x - 84
=> (72 + 84) + (-20x - 36x) = (30x - 6x) + (-240 - 84)
=> 156 - 56x = 24x - 324
=> 24x + 56x = 324 + 156
=> 80x = 480
=> x = 480 : 80 = 6
Vậy x = 6
b, 5(3x + 5) - 4(2x - 3) = 5x + 3(2x + 12) + 1
=> 15x + 25 - 8x + 12 = 5x + 6x + 36 + 1
=> (15x - 8x) + (25 + 12) = 11x + 37
=> 7x + 37 = 11x + 37
=> 11x - 7x = 0
=> x = 0
tìm x biết
a) (6x-3) (2x+4) + (4x-1) (5-3x) = -21
b) 6x (3x+5) - 2x (9x-2) + (17-x) (x-1) + x (x-18) =0
c) (15-2x) (4x+1) - (13-4x) (2x-3) - (x-1) (x+2) + x2=52
d) (8x-3) (3x+2) - (4x+7) (x+4) = (2x+1) (5x-1) - 33
Rút gọn hết ta được :
a/ 41x - 17 = -21
=> 41x = -4 => x = 4/41
b/ 34x - 17 = 0
=> 34x = 17
=> x = 17/34 = 1/2
c/ 19x + 56 = 52
=> 19x = -4
=> x = -4/19
d/ 20x2 - 16x - 34 = 10x2 + 3x - 34
=> 10x2 - 19x = 0
=> x(10x - 19) = 0
=> x = 0
hoặc 10x - 19 = 0 => 10x = 19 => x = 19/10
Vậy x = 0 ; x = 19/10
Rút gọn hết ta được :
a/ 41x - 17 = -21
=> 41x = -4 => x = 4/41
b/ 34x - 17 = 0
=> 34x = 17
=> x = 17/34 = 1/2
c/ 19x + 56 = 52
=> 19x = -4
=> x = -4/19
d/ 20x 2 - 16x - 34 = 10x 2 + 3x - 34
=> 10x 2 - 19x = 0
=> x(10x - 19) = 0
=> x = 0 hoặc 10x - 19 = 0
=> 10x = 19
=> x = 19/10
Vậy x = 0 ; x = 19/10
a) ( 6x - 3 ) ( 2x + 4 ) + ( 4x - 1 ) ( 5 - 3x ) = -21
<=> 12x2 + 24x - 6x - 12 + 20x - 12x2 - 5 + 3x = -21
<=> 41x = -21 + 12 + 5
<=> 41x = -4
<=> x = -4/41
B1:tìm x biết a, (-2+x^2)(x^2-2)(x^2-2)(x^2-2)(x^2-2)=1 b, (2x+3)(x-4)+(x-5)(x-2)=(3x-5)(x-4) c,(8x-3)(3x+2)-(4x+7)(x+4)=(4x+1)(5x-1) d, 2x^2+3(x-1)(x+1)=5x(x+1) e, (8-5x)(x+2)+4(x-2)(x+1)=(2+x)(2-x) f, 4(x-1)(x+5)-(x+2)(x+5)=3(x-1)(x+2)
Bạn nên viết lại đề bài cho sáng sủa, rõ ràng để người đọc dễ hiểu hơn.
f: =>4(x^2+4x-5)-x^2-7x-10=3(x^2+x-2)
=>4x^2+16x-20-x^2-7x-10-3x^2-3x+6=0
=>6x-24=0
=>x=4
e: =>8x+16-5x^2-10x+4(x^2-x-2)=4-x^2
=>-5x^2-2x+16+4x^2-4x-8=4-x^2
=>-6x+8=4
=>-6x=-4
=>x=2/3
d: =>2x^2+3x^2-3=5x^2+5x
=>5x=-3
=>x=-3/5
b: =>2x^2-8x+3x-12+x^2-7x+10=3x^2-12x-5x+20
=>-12x-2=-17x+20
=>5x=22
=>x=22/5
Chúng ta sẽ giải từng phương trình một:
a. Đặt , ta có:
1.Tìm x
a) (x - 5)(x + 5) - (x + 3)^2 + 3 (x - 2)^2 = (x + 1)^2 - (x + 4)(x - 4) +3x^2
b) (2x + 3)^2 + (x - 1)(x + 1) = 5 (x + 2)^2 - (x - 5)(x + 1) + (x + 4)^2
c) (-x + 5)(x - 2) + (x - 7)(x + 7) = (3x + 1)^2 - (3x - 2)(3x + 2)
d) (5x - 1)(x + 1) - 2(x - 3)^2 = (x + 2)(3x - 1) - (x + 4)^2 + (x^2 - x)
2.Rút gọn :
a) A= 3 (x - 1)^2 - (x + 1)^2 + 2(x - 3)(x + 3) - (2x + 3)^2 - (5 - 20x)
b) B= 5x (x - 7)(x + 7) - x (2x - 1)^2 - (x^3 + 4x^2 - 246x) - 175
c) C = -2x (3x + 2)^2 + (4x + 1)^2 + 2 (x^3 + 8x + 3x - 2 ) - (5 - x)
Rút gọn :
1. (2x-5)(3x+1)-(x-3)^2+(2x+5)^2-(3x+1)^3
2. (2x-1)(2x+1)-3x-2)(2x+3)-(x-1)^3+(2x+3)^3
3. (x-2)(x^2+2x+4)-(3x-2)^3+(3x-4)^2
4. (7x-1)(8x+2)-(2x-7)^2-(x-4)^3-(3x+1)^3
5. (5x-1)(5x+1)-(x+3)(x^2-3x+9)-(2x+4)^2-(3x-4)^2+(2x-5)^3
6. (4x-1)(x+2)-(2x+5)^2-(3x-7)^2+(2x+3)^3=(3x-1)^3
1: \(=6x^2+2x-15x-5-x^2+6x-9+4x^2+20x+25-27x^3-27x^2-9x-1\)
=-27x^3-18x^2+4x+10
2: =4x^2-1-6x^2-9x+4x+6-x^3+3x^2-3x+1+8x^3+36x^2+54x+27
=7x^3+37x^2+46x+33
5:
\(=25x^2-1-x^3-27-4x^2-16x-16-9x^2+24x-16+\left(2x-5\right)^3\)
\(=8x^3-60x^2+150-125+12x^2-x^3+8x-60\)
=7x^3-48x^2+8x-35
Bài 1:
a, (-2+x\(^2\))(x\(^2\)-2)(x\(^2\)-2)(x\(^2\)-2)(x\(^2\)-2)=1
b, (2x+3)(x-4)+(x-5)(x-2)=(3x-5)(x-4)
c, (8x-3)(3x+2)-(4x+7)(x+4)=(4x+1)(5x-1)
d,2x\(^2\)+3(x-1)(x+1)=5x(x+1)
e,(8-5x)(x+2)+4(x-2)(x+1)=(2+x)(2-x)
f, 4(x-1)(x+5)-(x+2)(x+5)=3(x-1)(x+2)
b: =>2x^2-8x+3x-12+x^2-7x+10=3x^2-17x+20
=>-12x-2=-17x+20
=>5x=22
=>x=22/5
c: =>24x^2+16x-9x-6-4x^2-16x-7x-28=20x^2-4x+5x-1
=>-16x-34=x-1
=>-17x=33
=>x=-33/17
d: =>2x^2+3x^2-3=5x^2+5x
=>5x=-3
=>x=-3/5
e: =>8x+16-5x^2-10x+4x^2-4x-8=4-x^2
=>-6x+8=4
=>-6x=-4
=>x=2/3
f: =>4(x^2+4x-5)-x^2-7x-10=3x^2+3x-6
=>4x^2+16x-20-4x^2-10x+4=0
=>6x=16
=>x=8/3
a) (x + 2)(x + 3)- (x- 2)(x + 5) = 0;
b) (2x + 3)(x - 4) + (x- 5)(x- 2) = (3x- 5)(x- 4);
c) (8- 5x)(x + 2) + 4(x- 2)(x + I ) + 2(x- 2)(x + 2) = 0;
d) (8x- 3)(3x + 2)- (4x + 7)(x + 4) = (2x + 1)(5x- I)- 33.
a) (x + 2)(x + 3) - (x - 2)(x + 5) = 0
<=> x2 + 3x + 2x + 6 - (x2 + 5x - 2x - 10) = 0
<=> x2 + 3x + 2x + 6 - x2 - 5x + 2x + 10 = 0
<=> 2x + 16 = 0
<=> 2x = -16
<=> x = -8
b) (2x + 3)(x - 4) + (x - 5)(x - 2) = (3x - 5)(x - 4)
<=> (2x + 3)(x - 4) + (x - 5)(x - 2) - (3x - 5)(x - 4) = 0
<=> 2x2 - 8x + 3x - 12 + x2 - 2x - 5x + 10 - (3x2 - 12x - 5x + 20) = 0
<=> 2x2 - 8x + 3x - 12 + x2 - 2x - 5x + 10 - 3x2 + 12x + 5x - 20 = 0
<=> 5x = 12 - 10 + 20
<=> 5x = 22
<=> x = 22/5
c) (8 - 5x)(x + 2) + 4(x - 2)(x + 1) + 2(x - 2)(x + 2) = 0
<=> 8x + 16 - 5x2 - 10x + (4x - 8)(x + 1) + 2(x2 - 4) = 0
<=> 8x + 16 - 5x2 - 10x + 4x2 + 4x - 8x - 8 + 2x2 - 8 = 0
<=> x2 - 6x = 0
<=> x(x - 6) = 0
<=> x = 0 hay x - 6 = 0
I<=> x = 6
d) (8x - 3)(3x + 2) - (4x + 7)(x + 4) = (2x + 1)(5x - 1) - 33
<=> 24x2 + 16x - 9x - 6 - (4x2 + 16x + 7x + 28) = 10x2 - 2x + 5x - 1 - 33
<=> 24x2 + 16x - 9x - 6 - 4x2 - 16x - 7x - 28 - 10x2 + 2x - 5x + 1 + 33 = 0
<=> 10x2 - 19x = 0
<=> x(10x - 19) = 0
<=> x = 0 hay 10x - 19 = 0
I <=> 10x = 19
I <=> x = 19/10
Bài 1: Giải các phương trình sau:
Câu 1.
a) 3x – 2 = 2x – 3 b) 3 – 4y + 24 + 6y = y + 27 + 3y
c) 7 – 2x = 22 – 3x d) 8x – 3 = 5x + 12
e) x – 12 + 4x = 25 + 2x – 1 f) x + 2x + 3x – 19 = 3x + 5
g) 11 + 8x – 3 = 5x – 3 + x h) 4 – 2x + 15 = 9x + 4 – 2x
2. a) 5 – (x – 6) = 4(3 – 2x) b) 2x(x + 2)2 – 8x2 = 2(x – 2)(x2 + 2x + 4)
c) 7 – (2x + 4) = – (x + 4) d) (x – 2)3 + (3x – 1)(3x + 1) = (x + 1)3
e) (x + 1)(2x – 3) = (2x – 1)(x + 5) f) (x – 1)3 – x(x + 1)2 = 5x(2 – x) – 11(x + 2)
g) (x – 1) – (2x – 1) = 9 – x h) (x – 3)(x + 4) – 2(3x – 2) = (x – 4)2
i) x(x + 3)2 – 3x = (x + 2)3 + 1 j) (x + 1)(x2 – x + 1) – 2x = x(x + 1)(x – 1)
3. a) 1,2 – (x – 0,8) = –2(0,9 + x) b) 3,6 – 0,5(2x + 1) = x – 0,25(2 – 4x)
c) 2,3x – 2(0,7 + 2x) = 3,6 – 1,7x d) 0,1 – 2(0,5t – 0,1) = 2(t – 2,5) – 0,7
e) 3 + 2,25x +2,6 = 2x + 5 + 0,4x f) 5x + 3,48 – 2,35x = 5,38 – 2,9x + 10,42
4.a) (5x-2)/3=(5-3x)/2 b)(10x+3)/12=1+((6+8x)/9)
c)2(x+3/5)=5-(13/5+x) d)7/8x-5(x-9)=(20x+1,5)/6
e)(7x-1)/6+2x=(16-x)/5 f)4(0,5-1,5x)=-(5x-6)/3
g)(3x+2)/2-(3x+1)/6=5/3+2x h)(x+4)/5-(x+4)=x/3-(x-2)/2
i) (4x+3)/5-(6x-2)/7=(5x+4)/3+3 k)(5x+2)/6-(8x-1)/3=(4x+2)/5-5
m)(2x-1)/5-(x-2)/3=(x+7)/15 n)1/4(x+3)=3-1/2(x+1)-1/3(x+2)
Bài 2 Tìm giá trị của k sao cho:
a. Phương trình: 2x + k = x – 1 có nghiệm x = – 2.
b. Phương trình: (2x + 1)(9x + 2k) – 5(x + 2) = 40 có nghiệm x = 2
c. Phương trình: 2(2x + 1) + 18 = 3(x + 2)(2x + k) có nghiệm x = 1
Bài 2:
a) Thay x=-2 vào phương trình 2x+k=x-1, ta được
2*(-2)+k=-2-1
⇔-4+k=-3
⇔k=-3-(-4)=-3+4=1
Vậy: Khi k=1 thì phương trình 2x+k=x-1 có nghiệm là x=-2
b) Thay x=2 vào phương trình (2x+1)(9x+2k)-5(x+2)=40, ta được
(2*2+1)*(9*2+2k)-5*(2+2)=40
⇔5*(18+2k)-20=40
⇔5*(18+2k)=40+20
⇔18+2k=12
⇔2k=12-18=-6
⇔k=-3
Vậy: khi k=-3 thì phương trình (2x+1)(9x+2k)-5(x+2)=40 có nghiệm là x=2
c) Thay x=1 vào phương trình 2(2x+1)+18=3(x+2)(2x+k), ta được
2*(2*1+1)+18=3*(1+2)*(2*1+k)
⇔2*3+18=3*3*(2+k)
⇔24=9*(2+k)
⇔\(2+k=\frac{24}{9}=\frac{8}{3}\)
\(\Leftrightarrow k=\frac{8}{3}-2=\frac{2}{3}\)
Vậy: khi \(k=\frac{2}{3}\) thì phương trình 2(2x+1)+18=3(x+2)(2x+k) có nghiệm là x=1
Tìm x,biết
a) ( x+2)×(x+3)-(x -2)×(x+5)=0
b) (2x+3)×(x-4)+(x-5)×(x-2)=(3x-5)×(x-4)
c) (8-5x)×(x+2)+4(x-2)×(x+1)+2(x-2)×(x+2)=0
d) (8x-3)×(3x+2)-(4x+7)×(x+4)=(2x+1)×(5x-1)-33