a)(6x^2+17x+12):(2x+3) b)(5x^2+13x-6):(5x-2) c)(-8x^2+22x-15):(2x-5) d)(14x^2-33x-5):(2x-5) e)(2x^3+7x^2+15x+6):(2x+1) f)(x^3+4x^2-11x-2):(x-2) g)(12x^3+2x^2+4x+3):(2x+1)
I) THỰC HIỆN PHÉP TÍNH a) 2x(x^2-4y) b)3x^2(x+3y) c) -1/2x^2(x-3) d) (x+6)(2x-7)+x e) (x-5)(2x+3)+x II phân tích đa thức thành nhân tử a) 6x^2+3xy b) 8x^2-10xy c) 3x(x-1)-y(1-x) d) x^2-2xy+y^2-64 e) 2x^2+3x-5 f) 16x-5x^2-3 g) x^2-5x-6 IIITÌM X BIẾT a)2x+1=0 b) -3x-5=0 c) -6x+7=0 d)(x+6)(2x+1)=0 e)2x^2+7x+3=0 f) (2x-3)(2x+1)=0 g) 2x(x-5)-x(3+2x)=26 h) 5x(x-1)=x-1 IV TÌM GTNN,GTLN. a) tìm giá trị nhỏ nhất x^2-6x+10 2x^2-6x b) tìm giá trị lớn nhất 4x-x^2-5 4x-x^2+3
Giải như sau.
(1)+(2)⇔x2−2x+1+√x2−2x+5=y2+√y2+4⇔(x2−2x+5)+√x2−2x+5=y2+4+√y2+4⇔√y2+4=√x2−2x+5⇒x=3y(1)+(2)⇔x2−2x+1+x2−2x+5=y2+y2+4⇔(x2−2x+5)+x2−2x+5=y2+4+y2+4⇔y2+4=x2−2x+5⇒x=3y
⇔√y2+4=√x2−2x+5⇔y2+4=x2−2x+5, chỗ này do hàm số f(x)=t2+tf(x)=t2+t đồng biến ∀t≥0∀t≥0
Công việc còn lại là của bạn !
\(\left(x+6\right)\left(2x+1\right)=0\)
<=> \(\orbr{\begin{cases}x+6=0\\2x+1=0\end{cases}}\)
<=> \(\orbr{\begin{cases}x=-6\\x=-\frac{1}{2}\end{cases}}\)
Vậy....
hk tốt
^^
Tìm x:
a) 4x(3x-7)-6(2x^2-5x+1)=12
b) (5x+3)(4x-1)+(10x-7)(-2x+3)=27
c) (8x-5)(3x+2)-(12x+7)(2x-1)=17
d) (5x+9)(6x-1)-(2x-3)(15x+1)=-190
a) 4x(3x-7)-6(2x2-5x+1)=12
=>4x.3x-4x.7-6.2x2-6.(-5x)-6.1=12
=>12x2-28x-12x2+30x-6=12
=>2x-6 =12
=>2x =12+6
=>2x =18
=>x =18:2
=>x =6
b)(5x+3)(4x-1)+(10x-7)(-2x+3)=27
=>5x.4x-5x.1+3.4x+3.(-1)+10x.(-2x)+10x.3-7.-(2x)-7.3=27
=>20x2-5x+12x-3-20x2+30x+14x-21=27
=>39x-36 =27
=>39x =27+36
=>39x =63
=>x =63:39
=>x =21/13
c) (8x-5)(3x+2)-(12x+7)(2x-1)=17
=>8x.3x+8x.2-5.3x-5.2-12x.2x-12x.(-1)+7.2x+7.(-1)=17
=>24x2+16x-15x-10-24x2+12x+14x-7=17
=>27x-17 =17
=>27x =17+17
=>27x =34
=>x =34:27
=>x =34/27
d) (5x+9)(6x-1)-(2x-3)(15x+1)=-190
=>30x2-5x+63x-9 - 30x2-2x-45x-3=-190
=>11x-12 =-190
=>11x =-190+12
=>11x =-178
=>x = -178:11
=>x =-178/11
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
a). (x^4+4x^3+5+8)÷(2x+5)
b). (5x^3+14x^2+12x+8)÷(x+2)
c). (4x^2-4x+1)÷(2x-1)
d). (2x^3+5x^2+6x+15)÷(2x+5)
Giúp mình với
a)3y-2y=2y-3
b)3-4x+24+6x=x+27+3x
c)5-(6-x)=4(3-2x)
d)4(x+3)=-7x+17
e)11x+42-2x=100-9x-22
g)2x+3/3 =5-4x/2
f)5x+3/12 = 1+2x/9
h)7x-1/6 = 16-x/5
i)x-3/5 = 6-1-2x/3
k)3x-2/6 - 5=3-2(x+7)/4
3x-7/2 + x+1/3=-16
x-x+1/3 = 2x+1/5
2x-1/3 - 5x+2/7
a, 3y-2y=2y-3
3y-2y-2y=3
-y=3
y=-3
b, 3-4x+24+6x=x+27+3x
-4x+6x-x-3x =27-3-24
-2x =0
x =0
c, 5-(6-x)=4.(3-2x)
5-6+x =12-8x
x+8x =12+6-5
9x =13
x =13/9
d, 4.(x+3)=-7x+17
4x+12 =-7x+17
4x+7x =17-12
11x =5
x =5/11
A) \(3y-2y=2y-3\) \(\Leftrightarrow y-2y=-3\) \(\Leftrightarrow y=3\)
B) \(3-4x+24+6x=x+27-3x\)\(\Leftrightarrow3-4x+24+6x-x-27-3x=0\)
\(\Leftrightarrow-2x=0\)\(\Leftrightarrow x=0\)
C) \(5-\left(6-x\right)=4\left(3-2x\right)\)\(\Leftrightarrow5-6x+x-12+8x=0\)\(\Leftrightarrow9x-13=0\)\(\Leftrightarrow x=\frac{13}{9}\)
D) \(4\left(x+3\right)=-7x+17\) \(\Leftrightarrow4x+12+7x-17=0\)\(\Leftrightarrow11x-5=0\)\(\Leftrightarrow x=\frac{5}{11}\)
E) \(11x+42-2x=100-9x-22\)\(\Leftrightarrow11x+42-2x-100+9x+22=0\)
\(\Leftrightarrow18x-36=0\)\(\Leftrightarrow x=2\)
F) \(5x+\frac{3}{12}=1+\frac{2x}{9}\)\(\Leftrightarrow180x+9-36-8x=0\)\(\Leftrightarrow172x-27=0\)\(\Leftrightarrow x=\frac{27}{172}\)
TK nka !!! Mk giải tiếp !!
Giúp mình với
a)3y-2y=2y-3
b)3-4x+24+6x=x+27+3x
c)5-(6-x)=4(3-2x)
d)4(x+3)=-7x+17
e)11x+42-2x=100-9x-22
g)2x+3/3 =5-4x/2
f)5x+3/12 = 1+2x/9
h)7x-1/6 = 16-x/5
i)x-3/5 = 6-1-2x/3
k)3x-2/6 - 5=3-2(x+7)/4
3x-7/2 + x+1/3=-16
x-x+1/3 = 2x+1/5
2x-1/3 - 5x+2/7
Bài 1 : làm tính chia
a, ( 6x^2 + 13x - 5x ) : 2x + 5
b, ( 12x^2 - 14x + 3 - 6x^3 + x^4) : (1- 4x + x^2)
c, ( 2x^2 - 5x^3 + 2x + 2x^4 -1 ):( x^2 - 2x-1)
d, ( x^2 + 2xy + y^2 ) : x +y
a: \(=\dfrac{6x^3+13x^2-5x}{2x+5}=\dfrac{6x^3+15x^2-2x^2-5x}{2x+5}=3x^2-x\)
b: \(=\dfrac{x^4-6x^3+12x^2-14x+3}{x^2-4x+1}\)
\(=\dfrac{x^4-4x^3+x^2-2x^3+8x^2-2x+3x^2-12x+3}{x^2-4x+1}\)
\(=x^2-2x+3\)
d: \(=\dfrac{\left(x+y\right)^2}{x+y}=x+y\)
câu 1:giải các pt và bpt sau: a,17x - 5(x+3)= 2x + 5 b,3/x+2 - 5/x-2 = 11x + 23/(x+2)(x-2) c,5x + 7 ≥ 3(x-1) d,3x-1/x+1 = -2/5 e,(2x-1)(2x+1)= 4x2 + 3x + 2 f,x-3^3 -7+3x g,7x-5 < 2(4x-1)+7
a: =>17x-5x-15-2x-5=0
=>10x-20=0
=>x=2
b: =>\(\dfrac{3x-6-5x-10}{\left(x+2\right)\left(x-2\right)}=\dfrac{11x+23}{\left(x+2\right)\left(x-2\right)}\)
=>11x+23=-2x-16
=>13x=-39
=>x=-3(nhận)
c: =>5x+7>=3x-3
=>2x>=-10
=>x>=-5
d: =>5(3x-1)=-2(x+1)
=>15x-5=-2x-2
=>17x=3
=>x=3/17
e: =>4x^2-1-4x^2-3x-2=0
=>-3x-3=0
=>x=-1
g: =>7x-5-8x+2-7<0
=>-x-10<0
=>x+10>0
=>x>-10