1.gia tri x thoa man x+(3x+1)2+1=9(x2+1)
2. rut gon bieu thucA=(a+b+c)2-(a-b-c)2-4b(a+c)+88
3.GTNN cua bieu thuc 4x2-4x-999+4x(1+x3)
4 cho hinh thang ABCDcoAB // CD , goc DAC=90 do , co duong cao AH , goc DAH =15 do . so do goc ACD la...
giai chi tiet giup to may bai nay nha
1. Cho tam giac ABC co trung tuyen AM . Goi I la trung diem cua AM. Tia BI cat AC tai D, qua M ke duong song song voi BD cat CD tai E. Biet BD=18cm , khih do ID = ? cm
2. gia tri lon nhat cua bieu thuc Q= 5-x2+2x2-4y2-4y
3 . gia tri cua x thoa man (12x-5)(4x-1)+(3x-7)(1-16x)=81 , x=?
4. x+y=3 , gia tri cua bieu thuc Q = x2+2xy+y2-4x-4y+1=?
5 . a+b+c=0 va abc=-2 thi a3+b3+c3= ?
6. rut gon bieu thuc(a2+b2)2-4a2b2voi a2-b2=5 ta duoc ket qua ?
1.Cho hình thang ABCD (AB//CD) co AB=13cm;CD=25cm,goc D=45 do.tinh dien tich hinh thang
2 gia tri nho nhat cua bieu thuc 4x2-4x-999+4x(1+3x3)
Cho bieu thuc A = ( 1/ x^2 - x + 1/x-1):x+1/x^2 -2x +1 ( x khac 0;1;-1)
a) Rut gon bieu thuc A
b) Tinh gia tri bieu thuc A khi x=2014/2013
c)Tim dieu kien cua x de A co gia tri lon hon 1
Mọi người tk mình đi mình đang bị âm nè!!!!!!
Ai tk mình mình tk lại nha !!!
1. cho phan tuc A=\(\frac{x^2+5x+4}{x^2+x-12}\)tap hop cac gia tri cua x de phan thuc A ko xac dinh la
2.cho hinh thang ABCD co dien tich la18cm2. duong cao AH =3cm . Do dai duong trung binh hinh thang la
3.cho x, y nguyen thoa man x2+4x+y2-12=0 . khi do gia tri lon nhat P=x2+y2 la Pmax=?
4.gia tri nho nhat cua bieu thuc A= \(\frac{x^2}{4}+3x+y^2-\frac{14}{5}y+\frac{425}{25}la\)
1.để Ak xđịnh thì x2+x-12=0
<=>x2+4x-3x-12=0
<=>x(x+4)-3(x+4)=0
<=>(x+4)(x-3)=0 <=> x=-4 hoặc x=3
Vậy để A k xđịnh <=> x=-4 hoặc x=3
**** cho mìk vs nha bạn
Bai1:
a- 3x^2 - 7x +2 b- a(x^2 +1 ) - x (a^2 +1)
Bai2 : Cho bieu thuc
A= (2+x/ 2-x - 4x^2 / x^2 -4 - 2-x/ 2+x ) : x^2 - 3x / 2x^2 - x ^3
a- Tim DKXD roi rut gon bieu thuc A ?
b- Tim gia tri cua x de A>0?
c- Tinh gia tri cua A TRong truong hop : \vbar x-7 \vbar=4
Giup mk nha moi nguoi !!!!!!!!!
Bài 2:
a: ĐKXĐ: \(x\notin\left\{0;2;-2;3\right\}\)\(A=\left(\dfrac{-\left(x+2\right)}{x-2}-\dfrac{4x^2}{\left(x-2\right)\left(x+2\right)}+\dfrac{x-2}{x+2}\right):\dfrac{x\left(x-3\right)}{x^2\left(2-x\right)}\)
\(=\dfrac{-x^2-4x-4-4x^2+x^2-4x+4}{\left(x-2\right)\left(x+2\right)}\cdot\dfrac{-x\left(x-2\right)}{x-3}\)
\(=\dfrac{-4x^2-8x}{\left(x+2\right)}\cdot\dfrac{-x}{x-3}\)
\(=\dfrac{-4x\left(x+2\right)}{x+2}\cdot\dfrac{-x}{x-3}=\dfrac{4x^2}{x-3}\)
b: Để A>0 thì x-3>0
hay x>3
1) Cho bieu thuc A=\(3+\frac{2}{x-1}\). Tinh gia tri cua bieu thuc A khi |2x-3|=1
2) Rut gon bieu thuc B=\(\frac{x}{x-1}\)-\(\frac{x-5}{x+1}\)-\(\frac{3-x}{1-x^2}\)
3) Tim cac gia tri nguyen cua x de bieu thuc \(\frac{B}{A}\)co gia tri nguyen duong
cho 2 bieu thuc A=x+x^2/2-x va B=2x/x+1+3/x-2-2x^2+1/x^2-x-2 a, tinh gia tri cua A khi /2x-3/=1 b,tim dieu kien xac dinh va rut gon bieu thuc B c,tim so nguyen x de P=A.B dat gia tri lon nhat
mk dang can gap
a:
ĐKXĐ: x<>2
|2x-3|=1
=>\(\left[{}\begin{matrix}2x-3=1\\2x-3=-1\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=2\left(loại\right)\\x=1\left(nhận\right)\end{matrix}\right.\)
Thay x=1 vào A, ta được:
\(A=\dfrac{1+1^2}{2-1}=\dfrac{2}{1}=2\)
b: ĐKXĐ: \(x\notin\left\{-1;2\right\}\)
\(B=\dfrac{2x}{x+1}+\dfrac{3}{x-2}-\dfrac{2x^2+1}{x^2-x-2}\)
\(=\dfrac{2x}{x+1}+\dfrac{3}{x-2}-\dfrac{2x^2+1}{\left(x-2\right)\left(x+1\right)}\)
\(=\dfrac{2x\left(x-2\right)+3\left(x+1\right)-2x^2-1}{\left(x+1\right)\left(x-2\right)}\)
\(=\dfrac{2x^2-4x+3x+3-2x^2-1}{\left(x+1\right)\left(x-2\right)}\)
\(=\dfrac{-x+2}{\left(x+1\right)\left(x-2\right)}=-\dfrac{1}{x+1}\)
c: \(P=A\cdot B=\dfrac{-1}{x+1}\cdot\dfrac{x\left(x+1\right)}{2-x}=\dfrac{x}{x-2}\)
\(=\dfrac{x-2+2}{x-2}=1+\dfrac{2}{x-2}\)
Để P lớn nhất thì \(\dfrac{2}{x-2}\) max
=>x-2=1
=>x=3(nhận)
Cho phan thuc B=(3\y+3)+(1\y-3)-(18\9-y2)
a)Tim dieu kien cua y de gia tri cua bieu thuc B duoc xac dinh
b)Rut gon bieu thuc B
c)Tinh gia tri cua B de B co gia tri nguyen
giai dum minh bai nay voi :c=x/2x-2+x^2+1/2-2x^2
a)tim x de a co nghia
b)rut gon bieu thuc c
c)tim gia tri cua x de bieu thuc kia =1/2
giúp mình cảm ơn nhìu nha !