( 158 x 168 - 158 x 58 ) : 11 : 10
Tính hợp lý:
( 158 x 168 - 79 x 58 ) : 11 : 10
(158x168-79x58):11:10
=(26 544-4582):11:10
=21 962:11:10
=21 962/11:10
=10981/55
( 158 x 168 - 79 x 58 ) : 11 : 10 = ( 158 x 168 - 79 x 2 x 29) : 11 : 10
= ( 158 x 168 - 158 x 29) : 11 : 10
= 158 x ( 168 - 29 ) : 11 : 10
= 158 x 139 : 11 : 10
= 21962 : 11 : 10
= 10981/55
1 , Tìm X
A , ( 1000 - 333 × X ) × 1000 - 999 = 1
B , 75% × X = 1
2, Tính
A , M = 50% × 1 1/3 × 10 × 7/35
B , 40404/70707 + 244 × 395 - 151 / 244 + 395 × 243
C , ( 158 × 68 - 158 × 58 ) : 11 : 10
(-34+100)-56
10-(47+30)
(37-58) - (27-158)
-(27-168)+(37-68)
(22-225)-(75-168)
254-(175+146+125)
ket qua phep tinh 1682 - 158 x 168 chia 110
-2009+x = 58-(158 -9)
tìm x thuộc Z biết
- 2009 + x = 58 - ( 158 - 9 )
- 2009 + x = 58 - ( 158 - 9 )
- 2009 + x = 58 - 149
- 2009 + x = -91
x = -91 - (-2009)
x = 1918
vậy................
Tính nhanh nha: 2.(-x+5)-5^2=(-3).(-7)
-37.(-58)+37.(-158)
-37 . (-58 ) + 37 . (-158 )
= -37 . ( -58 + 158 )
= -37 . 100
= -3700
1.tính nhanh 158\(^2+58^2-116.158\)
2.phân tích đa thức thành nhân tử
a.\(8x^2+6x\)
b.\(x^3-5x^2-4x+20\)
1. 1582 - 116.158 + 582
= 1582 - 2.58.158 + 582
= (158 - 58)2
= 1002 = 10000
2.a. 8x2 + 6x = 2x(4x + 3)
b, x3 - 5x2 - 4x + 20
= x3 - 4x - 5x2 + 20
= x(x2 - 4) - 5(x2 - 4)
= (x - 5)(x - 2)(x + 2)
3 | + | 3 | + … + | 3 | = | |
6 x 8 | 8 x 10 | 158 x 160 |
Đặt A = \(\dfrac{3}{6\cdot8}+\dfrac{3}{8\cdot10}+...+\dfrac{3}{158\cdot160}\)
A = \(\dfrac{3}{2}\cdot\left(\dfrac{2}{6\cdot8}+\dfrac{2}{8\cdot10}+...+\dfrac{2}{158\cdot160}\right)\)
A = \(\dfrac{3}{2}\cdot\left(\dfrac{1}{6}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{10}+...+\dfrac{1}{158}-\dfrac{1}{160}\right)\)
A = \(\dfrac{3}{2}\cdot\left(\dfrac{1}{6}-\dfrac{1}{160}\right)\)
A = \(\dfrac{3}{2}\cdot\dfrac{77}{480}\)
A = \(\dfrac{77}{320}\)
Vậy: A = \(\dfrac{77}{320}\)