\(x\left(x^2+2x+3\right)-x^2\left(x+2\right)=5x+7\)
\(\Rightarrow x^3+2x^2+3x-x^3-2x^2=5x+7\)
\(\Rightarrow3x=5x+7\)
\(\Rightarrow3x-5x=7\)
\(\Rightarrow-2x=7\)
\(\Rightarrow x=-\dfrac{7}{2}\)
BT: Tìm x
a) 2x.(x-3)-x(2x+1)-3.(x+5)=11
b) x.(x-1)-(x^2+3x-5)-2.(x+3)=7
c) 5x.(x-7)-(5x+1).x-(x+3).2=13
d) (2x^2-3x+5)-2x.(x-3)+(x-1).(-2)=10
Tìm x, biết
a) 4(x+2) - 7(2x-1) + 9(3x-4) = 30
b)2(5x-8) - 3(4x-5) = 4(3x-4) + 11
c) 4x2 + 3(2x2+1) = 2x(5x-7)
d) x(x2-7) = 2x(\(\dfrac{1}{2}\)x2+6) + 8
16 Tìm x, biết
a) 4(x+2)-7(2x-1)+9(3x-4)=30 ; b) 2(5x-8)-3(4x-5)=4(3x-4)+11
c) 5x(1-2x)-10(x+8)=0 ; d) (5x-3).4x-2x.(10x-3)=15
Thực hiện phép tính :
a)5x2 - 3x . (x-2)
b) 3x.(x-5)-5x.(x+7)
c) 5x.(1/5x-2)=3.(6-1/3x2)
d) 7x.(x-5)+3.(x-2)
e) 5-4x.(x-2)+4x2
f)4x.(2x-3)-5x.(x-2)
Tìm X :
A) x.(x-2)-(x+3).x+7+9x=6
B)(3x-5).(7-5x)-(5x+2).(2-3x)=4
C)(x+2).(x mũ2 -2x+4)-(x.3+3)=14x
D)(x mũ2 -x+1).(x+1)-x mũ3 -3x=2
GẤP MN HỘ E ...!!🙂😣
Câu 1: Chứng minh giá trị của biểu thức không phụ thuộc vào biến x
A = x (5x - 3) - x2 ( x - 1) + x (x2 - 6x) + 3x - 10
B = ( 2x + 1) x - x2 (x + 2) + x3 - x + 3
C = 5x ( x2 - 7x + 2) - x2 (5x - 8) + 27x2 - 10x + 2
Câu 2: Tìm x:
1. 4x (3x + 2) - 6x (2x + 5) + 21 (x - 1) = 0
2. 5x (12x + 7) - 3x (20x - 5) = -100
3. (x2 -1) - 3x (3x2 - 2) x + 2x = 2
4. 10 (3x - 2) - 3 (5x + 2) + 5 (11 - 4x) = 25
HELP ME T^T
A,(x²-1)(x²+5x+6)=60
B,(x²-6x)²-2(x-3)²=81
C,(5x+3)²-(2x-7)²=x-40
D,x(x+1)(x+2)(x+3)=120
E,x³+5x²-10x-8=0
Tìm x biết:
1. -3x(x-5)+5(x-1)+3x2=4-x
2. 7x(x-2)-5(x-1)=21x2-14x2+3
3. 3(5x-1)-x(x-2)+x2-13x=7
4. \(\dfrac{1}{5}\)x(10x-15)-2x(x-5)=12
Rút gọn biểu thức
a) 7x(4y-x) + 4y (y-7x) - (2y^2 -3,5x)
b) 3x(5x^2 -2) -5x^2 (7+3x) -2,5( 2-14x^2)
c) 2x^3 (x-1) (x+1) -5x(x+1)
