Tính \(\frac{45.16-17}{28+45.15}\)
\(\frac{45.16-17}{45.15+28}\)
= 45.(15+1)-17/45.15+28
= 45.15+45-17/45.15+28
= 45.15+28/45.15+28
= 1
Tk mk nha
= 45.(15+1)-17/45.15+28
= 45.15+45-17/45.15+28
= 45.15+28/45.15+28
= 1
\(\frac{45.16-17}{45.15+28}\)
\(=\frac{720-17}{675+28}\)
\(=1\)
Tính :
\(\frac{45.16-17}{45.15+28}\)
Tìm x :
5x + 5x+2 = 650
Tính:
\(\frac{45\cdot16-17}{45\cdot15+28}\)
\(=\frac{45\cdot15+45-17}{45\cdot15+28}\)
\(=\frac{45\cdot15+28}{45\cdot15+28}=1.\)
Tìm x:
\(5^x+5^{x+2}=650\)
=>\(5^x+5^x\cdot25=650\)
=>\(5^x\cdot26=650\)
Dễ rồi nhá.
Bài 1 : Ta có : \(\frac{45.16-17}{45.15+28}=\frac{45.16-17}{45.15+45-17}=\frac{45.16-17}{45\left(15+1\right)-17}=\frac{45.16-17}{45.16-17}=1\)
Bài 2 :
Ta có 5x + 5x + 2 = 650
=> 5x(1 + 52) = 650
=> 5x . 26 = 650
=> 5x = 650 : 26
=> 5x = 25
=> 5x = 52
=> x = 2
Tính nhanh \(\dfrac{45.16-17}{28+45.15}\)
Ta có:
45 . 16 - 17 = 45. (15 +1) - 17
= 45 . 15 + 1.45 - 17
= 45 . 15 + (45 - 17)
= 45 . 15 + 28
vậy \(\dfrac{45.16-17}{45.15+28}=\dfrac{45.15+28}{45.15+28}=1\)
\(\dfrac{45.16-17}{28+45.15}\)
= \(\dfrac{45.\left(15+1\right)-17}{28+45.15}\)
= \(\dfrac{45.15+\left(45-17\right)}{28+45.15}\)
= \(\dfrac{45.15+27}{27+45.15}\)
= 1
~ Chúc bạn học giỏi ! ~
tính bằng cách hợp lí
\(\frac{45.16-17}{45.15+58}\)
\(=\frac{45.15+45-17}{45.15+58}=\frac{45.15+28}{45.15+58}=???\)
ủa đề sai à ta?
KHÔNG tính hãy so sánh:
a)45.16-17 với 28+45.15
b)7256.4375-725voi 3650+4375.7255
A, 45.16-17=45.15+45-17=28+45.15
Giờ ta thấy cả 2 vế đều có 45.15
Mà
28=28suy ra 45.16-27=28+45.15
B, xét 3650 +4375.7255
==3650+4375.7256-4375=4375.7256-725
Suy ra 2 vế bằng nhau!☺
giúp mình nha
tính hợp lí;
a)45.16-17:28+45.15
b)27.45+27.55:2+4+6+8+........+16+18
tính nhanh
\(\frac{\left(456.11+912\right).37}{13.74}\)
\(\frac{864.48-432.96}{864.48.432}\)
\(\frac{16.17-5}{16.16+11}\)
\(\frac{45.16-17}{28+45.15}\)
\(\frac{7256.4375-725}{3650+4375.7255}\)
\(\frac{\left(456.11+912\right).37}{13.74}\)
\(=\frac{\left(456.11+456.2\right).37}{13.37.2}\)
\(=\frac{[456.\left(11+2\right).37}{13.37.2}\)
\(=\frac{456.13}{13.2}\)
\(=\frac{456}{2}=228\)
1)Tính nhanh
a) (56.27+56.35):62
b)884.48-432:96/864.48.432
c)45.16-17/28+45.15
d)27.45+27.55/2+4+6+........+18
2) Tìm X thuộc N , biết:
a)[(6.X-39):3].28=5628
b)(16.15):2=(X+70).14-20
c)6060:50.X+20/X=101
a,(56.27+56.35):62
=56x(27+35):62
=56.62:62
=56.1
=56
a)=>56.(27+32):62
=>56.62:62
=>56.1
=56
b)tự làm
c)=>45.(16+15)-17/28
=>45.31-17/28
=>1395-17/28
=19513/14
d)=>27.(45+55)/(18+2).9:2
=>2700/90
=30
Làm bằng cách nào cho hợp lí nhất :
a)\(\frac{16.17-5}{16.16+11}\)
b) \(\frac{45.16-17}{28+45.15}\)
c) \(\frac{7256.4375-725}{3650+4375.725}\)
chúc các bạn làm bài đúng nhất :))
a)\(\frac{16.17-5}{16.16+11}=\frac{16.17-16+11}{16.16+11}\)\(=\frac{16.\left(17-1\right)+11}{16.16+11}=\frac{16.16+11}{16.16+11}=1\)
b) \(\frac{45.16-17}{28+45.15}=\frac{45.\left(15+1\right)-17}{28+45.15}\)\(=\frac{45.15+45-17}{28+45.15}=\frac{45.15+28}{28+45.15}=1\)
c) \(\frac{7256.4375-725}{3650+4375.7255}=\frac{\left(7255+1\right).4375-725}{3650+4375.7255}\)\(=\frac{7255.4375+4375-725}{3650+4375.7255}\)\(=\frac{7255.4375+3650}{3650+4375.7255}=1\)
Câu C nhớ sửa 725 thành 7255 nha !
Bài giải
\(a,\text{ }\frac{16\cdot17-5}{16\cdot16+11}=\frac{16\cdot16+16-5}{16\cdot16+11}=\frac{16\cdot16+11}{16\cdot16+11}=1\)
\(b,\text{ }\frac{45\cdot16-17}{28+45\cdot15}=\frac{45\cdot15+45-17}{45\cdot15+28}=\frac{45\cdot15+28}{45\cdot15+28}=1\)
\(c,\text{ }\frac{7256\cdot4375-725}{3650+4375\cdot7255}=\frac{4375\cdot7255+4375-725}{4375\cdot7255+3650}=\frac{4375\cdot7255+3650}{4375\cdot7255+3650}=1\)