1,p(x) = 3x^3+5x^2-26x+8
2,p(x)=x^3-7x^2+14x-8
3,p(x)=x^3-x^2-14x+24
4,p(x)=x^4-5x^3+5x^2+5x-6
giải phương trình :
a,\(\sqrt{5x^2+14x+9}-5\sqrt{x+1}=\sqrt{x^2-x-2}\)
b, \(x^2-8x+17=3\sqrt{x^3-7x+6}\)
c, \(x^2+5x+2=4\sqrt{x^3+3x^2+x-1}\)
1:
1). 2x-3=11-5x
2). 0,5(2x-9)=1,5x(x-5)
3). 28(x-1)-9(x-2)=14x
4). 8(3x-2)-14x=2(4-7x)+18x
5). 2(x-5)-6(1-2x)=3x+2
6). 2x-3=3(x-1)+x+2
1)2x-3=11-5x
2x+5x=11+3
7x =14
x=2.
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)
Bài 1
a) 2x^3 + 5x^2 + 5x + 3
b) 4x^3 + x^2 + x - 3
c) 5x^3 - 12x^2 + 14x - 4
d) 6x^3 - 7x^2 + 5x - 2
e) 3x^3 + 19x^2 + 4x - 12
\(a,2x^3+5x^2+5x+3\)
\(=2x^3+3x^2+2x^2+3x+2x+3\)
\(=x^2\left(2x+3\right)+x\left(2x+3\right)+\left(2x+3\right)\)
\(=\left(2x+3\right)\left(x^2+x+1\right)\)
b) = 4x^3 - 3x^2 + 4x^2 - 3x + 4x - 3
= x^2(4x-3) + x(4x - 3) + 4x - 3
= (4x - 3)(x^2 + x + 1)
c) = 5x^3 - 2x^2 - 10x^2 + 4x + 10x - 4
= x^2(5x - 2) - 2x(5x - 2) + 2(5x - 2)
= (5x - 2)(x^2 - 2x + 2)
d)= 6x^3 - 4x^2 - 3x^2 + 2x + 3x - 2
= 2x^2(3x - 2) - x(3x - 2) + (3x - 2)
= (3x-2)(2x^2-x+1)
e) = 3x^3 - 2x^2 + 21x^2 - 14x + 18x - 12
= x^2( 3x - 2) + 7x(3x - 2) + 6(3x - 2)
= (3x - 2)(x^2 + 7x + 6)
= (3x - 2)(x+1)(x+6)
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)
BÀI 2: rút gọn biểu thức
a) 2x( 5-3x^2) - 10( 6+x)
b)3(-x+2)-6( 1-x+5x^20)
c) 7x( 2-5x^2+1/2x^3)- 14x( 1-2x^2)
a) \(2x\left(5-3x^2\right)-10\left(6+x\right)\)
\(=10x-6x^3-60-10x\)
\(=\) \(-6x^3-60\)
a) \(2x\left(5-3x^2\right)-10\left(6+x\right)\\ =2x.5-2x.3x^2-10.6-10.x\\ =10x-6x^3-60-10x\)
b) \(3\left(-x+2\right)-6\left(1-x+5x^{20}\right)\\ =-3.x+3.2-6.1+6.x-5.5x^{20}\\ =-3x+6-6+6x-25x^{20}=25x^{20}+3x\)
c) \(7x\left(2-5x^2+\dfrac{1}{2}x^3\right)-14x\left(1-2x^2\right)\\ =7x.2-7x.5x^2+7x.\dfrac{1}{2}x^3-14x.1+14x.2x^2\\ =14x-25x^3+\dfrac{7}{2}x^4-14x+28x^3=3x^2+\dfrac{7}{2}x^4\)
b) \(3\left(-x+2\right)-6\left(1-x+5x^{20}\right)\)
\(=-3x+6-6+6x-30x^{20}\)
\(=3x-30x^{20}\)
Bài 1
a) 2x^3 + 5x^2 + 5x + 3
b) 4x^3 + x^2 + x - 3
c) 5x^3 - 12x^2 + 14x - 4
d) 6x^3 - 7x^2 + 5x - 2
e) 3x^3 + 19x^2 + 4x - 12
1. TÌm x:
a)4x^2-2x+3-4x.(x-5)=7x-3
b)-3x.(x-5)+5.(x-1)+3x^2=4x
c)7x.(x-2)-5.(x-1)=21x^2-14x^2+3
d)3.(5x-1)-x.(x-2)+x^2-13x=7
e) 1/5x.(10x-15)-2x.(x-5)=12
a) 4x2 - 2x + 3 - 4x.(x - 5) = 7x - 3
--> 4x2 - 2x + 3 - 4x2 + 20x = 7x - 3
--> 4x2 - 2x - 4x2 + 20x - 7x = -3 - 3
--> 11x = -6
--> x = \(\frac{-6}{11}\)
b) -3x.(x - 5) + 5.(x - 1) + 3x2 = 4x
--> -3x2 + 15x + 5x - 5 + 3x2 = 4x
--> -3x2 + 15x + 5x + 3x2 - 4x = 5
--> 16x = 5
--> x = \(\frac{5}{16}\)
c) 7x.(x - 2) - 5.(x - 1) = 21x2 - 14x2 + 3
--> 7x2 - 14x - 5x + 5 = 7x2 + 3
--> 7x2 - 14x - 5x - 7x2 = -5 + 3
--> -19x = -2
--> x = \(\frac{2}{19}\)
d) 3.(5x - 1) - x.(x - 2) + x2 - 13x = 7
--> 15x - 3 - x2 + 2x + x2 - 13x = 7
--> 15x - x2 + 2x + x2 - 13x = 3 + 7
--> 4x = 10
--> x = \(\frac{5}{2}\)
e) \(\frac{1}{5}\)x.(10x - 15) - 2x.(x - 5) = 12
--> 2x2 - 3x - 2x2 + 10x = 12
--> 7x = 12
--> x = \(\frac{12}{7}\)
~ Học tốt ~
1. TÌm x:
a)4x^2-2x+3-4x.(x-5)=7x-3
b)-3x.(x-5)+5.(x-1)+3x^2=4x
c)7x.(x-2)-5.(x-1)=21x^2-14x^2+3
d)3.(5x-1)-x.(x-2)+x^2-13x=7
e) 1/5x.(10x-15)-2x.(x-5)=12
a) 4x2 - 2x + 3 - 4x(x - 5) = 7x - 3
=> 4x2 - 2x + 3 - 4x2 + 20x = 7x - 3
=> 18x + 3 = 7x - 3
=> 18x - 7x = -3 - 3
=> 11x = -6
=> x = -6/11
b) -3x(x - 5) + 5(x - 1) + 3x2 = 4x
=> -3x2 + 15x + 5x - 5 + 3x2 = 4x
=> 20x - 5 = 4x
=> 20x - 4x = 5
=> 16x = 5
=> x = 5/16
\(c,7x\left(x-2\right)-5\left(x-1\right)=21x^2-14x^2+3\)
\(\Leftrightarrow7x^2-14x-5x+5=7x^2+3\)
\(\Leftrightarrow7x^2-7x^2-19x=3-5\)
\(\Leftrightarrow-19x=-2\)
\(\Leftrightarrow x=\frac{2}{19}\)
a) 4x2 - 2x + 3 - 4x.(x - 5) = 7x - 3
<=> 18x + 3 = 7x - 3
<=> 18x = 7x - 3 - 3
<=> 18x = 7x - 6
<=> 18x - 7x = -6
<=> 11x = -6
<=> x = -6/11
=> x = -6/11
b) -3x.(x - 5) + 5.(x - 1) + 3x2 = 4x
<=> 20x - 5 = 4x
<=> 20x = 4x + 5
<=> 20x - 4x = 5
<=> 16x = 5
<=> x = 5/16
=> x = 5/16
c) 7x.(x - 2) - 5.(x - 1) = 21x2 - 14x2 + 3
<=> 7x.(x - 2) - 5.(x - 1) = 7x2 + 3
<=> 7x2 - 19x + 5 = 7x2 + 3
<=> 7x2 - 19x = 7x2 + 3 - 5
<=> 7x2 - 19x = 7x2 - 2
<=> 7x2 - 19x - 7x2 = -2
<=> -19x = -2
<=> x = 2/19
=> x = 2/19
d) 3.(5x - 1) - x.(x - 2) + x2 - 13x = 7
<=> 4x - 3 = 7
<=> 4x = 7 + 3
<=> 4x = 10
<=> x = 10/4
=> x = 5/2
e) 1/5x.(10x - 15) - 2x.(x - 5) = 12
<=> x(2x - 3) - 2x(x - 5) = 12
<=> 7x = 12
<=> x = 12/7
=> x = 12/7