17/15_{3/17 +2/15}
1) Tính
a) (217+172).(915_159).(42-24)
b) (12+23+34+45).(13+23+33+43).(38+812)
( -17/15-9/17) -( 2/3-9/17)
=-17/15-9/17-2/3+9/17
=-17/15-10/15
=-27/15
=-9/5
Giải:
\(\left(\dfrac{-17}{15}-\dfrac{9}{17}\right)-\left(\dfrac{2}{3}-\dfrac{9}{17}\right)\)
⇔ \(\dfrac{-17}{15}-\dfrac{9}{17}-\dfrac{2}{3}+\dfrac{9}{17}\)
⇔\(\dfrac{-17}{15}-\dfrac{10}{15}\)
\(\Leftrightarrow\dfrac{-27}{15}=\dfrac{-9}{5}\)
=-17/15-9/17-2/3+9/17
=-17/15-10/15
=-27/15
=-9/5
(3+0,75-3/19)/(5/2+0,625 -5/38)×(15+15/17-15/144+15/34)/(2+3/17-2/144)+2018
So sánh
A=17^15+3 và B= 17^15
17^15-2 17^15-5
ta có:\(A=\frac{17^{15}+3}{17^{15}-2}=\frac{17^{15}-2+5}{17^{15}-2}=\frac{17^{15}-2}{17^{15}-2}+\frac{5}{17^{15}-2}=1+\frac{5}{17^{15}-2}\)
\(B=\frac{17^{15}}{17^{15}-5}=\frac{17^{15}-5+5}{17^{15}-5}=\frac{17^{15}-5}{17^{15}-5}+\frac{5}{17^{15}-5}=1+\frac{5}{17^{15}-5}\)
vì 1715-2>1715-5
=>\(\frac{5}{17^{15}-2}<\frac{5}{17^{15}-5}\)
=>A<B
(2^17+17^2).(9^15-3^15).(2^4-4^2)
(217 + 172).(915 - 315).(24 - 42)
= (217 + 172).(915 - 315).(16 - 16)
= (217 + 172).(915 - 315).0
= 0
(217 + 172) (915 - 315) (24 - 42)
= (217 + 172).(915 - 315).(16 - 16)
= (217 + 172).(915 - 315).0 = 0
2 phần 3 . 15 phần 17 - 5 phần 3 nhân 15 phần 17
\(\dfrac{2}{3}.\dfrac{15}{17}-\dfrac{5}{3}.\dfrac{15}{17}\)
= \(\dfrac{15}{17}.\left(\dfrac{2}{3}-\dfrac{5}{3}\right)\)
\(=\dfrac{15}{17}.\left(-1\right)=-\dfrac{15}{17}\)
đúng đề ko?
\(\dfrac{2}{3}\).\(\dfrac{15}{17}\)-\(\dfrac{5}{3}\).\(\dfrac{15}{17}\)
= \(\dfrac{15}{17}\).(\(\dfrac{2}{3}\)-\(\dfrac{5}{3}\))
= \(\dfrac{15}{17}\).(-1)
=\(-\dfrac{15}{17}\)
\(\dfrac{2}{3}\cdot\dfrac{15}{17}-\dfrac{5}{3}\cdot\dfrac{15}{17}\)
\(=\dfrac{15}{17}\left(\dfrac{2}{3}-\dfrac{5}{3}\right)\)
\(=-\dfrac{15}{17}\)
B=((3+0,75)-3/19)/(5/+0,625-5/38) × (15+15/17-15/144+15/34)/(2+3/17-2/144)+2018
( 2^17+17^2)×(9^15-3^15)×(2^4-4^2)
Giúp mk vs
Bài 13: Dấu <, =, >
10 … 10 + 3
11 + 2…. 2 + 11
9 … 10 + 9
10 … 10 + 0
17 – 4 … 14 - 3
18 – 4 … 12
15 … 15 – 1
17 + 1… 17 + 2
12+ 5 … 16
16 … 19 - 3
15 – 4 … 10 + 1
19 – 3 … 11
10 < 10 + 3
11 + 2=2 + 11
9 < 10 + 9
10 = 10 + 0
17 – 4 > 14 - 3
18 – 4 >12
15 > 15 – 1
17 + 1<17 + 2
12+ 5 > 16
16 =19 - 3
15 – 4 =10 + 1
19 – 3 >11