Cho bieu thuc A = 2002 + 690 : ( a + 3 )
Tim gia tri cua a de bieu thuc A = 2005
voi A = 2 gia tri cua bieu thuc A la
A =
tim gia tri cua bieu thuc a de bieu thuc A co gia tri lon nhat tim gia tri lon nhat do
Cho bieu thuc: A= 2,25 ×( a-12,5)+4,35
a) Tim gia tri cua bieu thuc A khi a= 112,5
b) Tin gia tri cua a de bieu thuc A co gia tri be nhat, gia tri be nhat la bao nhieu?
A = 2,25 x ( 112,5 -12,5 ) + 4,35
= 2,25 x 100 + 4,35
= 225 + 4,35
= 229,35
cho bieu thuc A=2,45*(a+64,36)-45
a tinh gia tri bieu thuc A khi a=35,64
b tim gia tri cua A de bieu thuc A =126,5
b. Neu A =126.5 thì 126.5=2.45 x (a+64.36) -45
= 2.45 x (a+64.36) 126.5 + 45
= 2.45 x (a+64.36) = 171.5
= a+64.36 = 171.5 : 24.5
a+64.36 = 70
a = 70 - 64.36
a = 5.64
a,thay a=35,64vào bthuc đã cho ta đc:
A= 2,45x(35,64 +64,36)-45=2,45x100-45=200
b,để A=126,5 thì 2,45x(a+64,36)-45=126,5
=>2,45a+157,682-45=126,5
=>2,45a=13,818
=>a=5,64
cistian ronaldo
cho bieu thuc A=[x+2/x^2-x+x-2/x^2+x].x^2-1/x^2+2
a) tim dieu kien cua x de gia tri cua bieu thuc A duoc xac dinh
b) tinh gia tri cua bieu thuc A voi x = -200
a) \(A=\left[\dfrac{x+2}{x^2-x}+\dfrac{x-2}{x^2+x}\right].\dfrac{x^2-1}{x^2-x}\)
\(A=\left[\dfrac{x+2}{x\left(x-1\right)}+\dfrac{x-2}{x\left(x+1\right)}\right].\dfrac{x^2-1}{x^2+2}\)
\(A=\left[\dfrac{\left(x+2\right)\left(x+1\right)+\left(x-2\right)\left(x-1\right)}{x\left(x-1\right)\left(x+1\right)}\right].\dfrac{x^2-1}{x^2+2}\)
\(A=\left[\dfrac{x^2+2x+x+2+x^2-2x-x+2}{x\left(x-1\right)\left(x+1\right)}\right].\dfrac{x^2-1}{x^2+2}\)
\(A=\dfrac{2x^2+4}{x\left(x^2-1\right)}.\dfrac{x^2-1}{x^2+2}\)
\(A=\dfrac{2\left(x^2+2\right)\left(x^2-1\right)}{x\left(x^2-1\right)\left(x^2+2\right)}=\dfrac{2}{x}\)
b) Thay \(x=-200\) vào biểu thức \(A=\dfrac{2}{x}\) ta được :
\(A=\dfrac{2}{x}=\dfrac{2}{-200}=\dfrac{-2}{200}=\dfrac{-1}{100}\)
Cau 9 : Cho bieu thuc : A= 2002 - 1998 \ [ a - 16 ] /316 + 6,84 \ 0,01 . Tinh gia tri bieu thuc a de bie thuc A co gia tri nho nhat ?
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
Cho biểu thức A = x^2+3/x-2
a tim dieu kien cua x de gia tri cua bieu thuc khong xac dinh duoc
b. Voi nhung gia tri nao cua x thi bieu thuc A nhan gia tri la so a
B = 2002 : 1998 : ( a - 16 )
a )tinh gia tri bieu thuc B khi a = 1015
b )tim gia tri so tu nhien a de bieu thuc B co gia tri nho nhat , gia tri nho nhat bang bao nhieu
phan a minh ra rui bang 1001 phan 1000 nhung phan b thi minh ko bit lam cac ban oi giup mink voi
Cho bieu thuc:P=\(\dfrac{\left(a+3\right)^2}{a^2+3a}\times\left(1-\dfrac{6a-18}{a^2-9}\right)\)voi a ≠0;a≠ +-3
a)rut gon bieu thuc P
b)tim gia tri cua a de P= -2
c)tim cac gia tri nguyen cua a de bieu thuc P co gia tri nguyen
mng giup minh voi mai thi rui!
a: \(P=\dfrac{a+3}{a}\cdot\dfrac{a^2-9-6a+18}{\left(a-3\right)\left(a+3\right)}\)
\(=\dfrac{\left(a-3\right)^2}{a\left(a-3\right)}=\dfrac{a-3}{a}\)
b: Để P=-2 thì -2a=a-3
=>-3a=-3
=>a=1
c: Để P nguyên thì a-3 chia hết cho a
=>-3 chia hết cho a
mà a<>0; a<>3; a<>-3
nên \(a\in\left\{1;-1\right\}\)