Thuc hien phep tinh:
a.3/7.11/15+3/7:15/14+2/7
b.(-7/15).5/8.15/-7(-32)
c.[(1/9:8/27):-1/3]:81/128
d.-66(1/2-1/3+1/11)+124(-37)+63(-124)
tim gia tri lon nhat cua bieu thuc :
a) C= 5+ 15/ 4 I 3x+7 I +3
b) D= 2 I 7x+5I +11/ I 7x+5I +4
tim GTNN cua bieu thuc :
a) A= I x+1I + 1,7
b) B= I x-2/3I +3/7
c) C= 5+ -8/ 4x I5x+7I 24
cho bieu thuc:
A=(6-2/3+1/2)-(5+5/3-3/2)-(3-7/3+5/2)
hay tinh gia tri cua A theo hai cach
cach 1:truoc het tinh gia tri tung bieu thuc trong ngoac
cach 2:bo dau ngoac roi nhom cac so hang thich hop
tinh gia tri cua bieu thuc B=1.2.3+2.3.4+3.4.5+5.6.7+...+17.18.19
Bài 1: Tính tổng (tính hợp lý nếu có thể)
a) ( -37) +14+ 26+ 37 b) (- 24)+ 6+ 10 +24
c) 15+ 23 +( -25) +(- 23) d) 60 +33+ ( -50)+ (- 33)
e) ( -16)+ (- 209) +( -14)+ 209 f)-32 + (-54):[(-2)8+7].(-2)2
1,timx,y biet
a,/x-7/+5=2x-3
b,4x-/5-x/2=2
c,/4x-3/+/5y+7,5/=0
2,tim gia tri nho nhat cua bieu thuc sau
A=/3,7-x+25/
B=/2x+1/+/y-2/+2018
Tinh gia tri bieu thuc sau:a.(2/3)^3^0-(5/3-3/4)^2. b.(53/4-59/27-65/6).230.1/25+187/4):(10/7+10/3):(37/7-100/7)
Tinh gia tri bieu thuc:
a)A=5x+8xy+5y voi x+y=2/5;xy=3/4
b)B=2xy+7xyz-2xz voi x=3/7;y-z=5/2;y.z=-1
tim cac gia tri cua x de bieu thuc sau nhan gia tri duong
a) x mu 2 + 4x b)2x mu 2 - 4x c)(x-3)(x+7) d)5(3x +1 )(4x-3) e)(1/2-x)(1/3-x)