15 + 25 + 35 + 45 + 55 =
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
15 + 25 + 35 + 45 + 55 + 65 + 75 + 85
= (15 + 85) + (25 + 75) + (35 + 65) + (45 + 55)
= 100 + 100 + 100 + 100
= 400
15+25+35+45+55+65+75+85
=(15+85)+(25+75)+(35+65)+(45+55)
=100+100+100+100
=400
![](https://rs.olm.vn/images/avt/0.png?1311)
= ( 5 + 95 ) + ( 15 + 85 ) + ( 25 + 75 ) + ( 35 + 65 ) + ( 45 + 55 )
= 100 + 100 + 100 + 100 + 100
= 5 x 100
= 500
![](https://rs.olm.vn/images/avt/0.png?1311)
5 - 10 + 15 - 20 + 25 - 30 + 35 - 40 + 45 - 50 + 55
= -5 + -5 + -5 + -5 + -5 + 55
= -25 + 55
= 30
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{x-55}{45}+\dfrac{x-30}{35}+\dfrac{x-25}{25}+\dfrac{x-40}{15}=10\)
\(< =>\dfrac{x-55}{45}+\dfrac{x-30}{35}+\dfrac{x-25}{25}+\dfrac{x-40}{15}-10=0\)
\(< =>\dfrac{x-55}{45}-1+\dfrac{x-30}{35}-2+\dfrac{x-25}{25}-3+\dfrac{x-40}{15}-4=0\)
\(< =>\dfrac{x-100}{45}+\dfrac{x-100}{35}+\dfrac{x-100}{25}+\dfrac{x-100}{15}=0\)
\(< =>\left(x-100\right)\left(\dfrac{1}{45}+\dfrac{1}{35}+\dfrac{1}{25}+\dfrac{1}{15}\right)=0\)
\(< =>x-100=0\left(\dfrac{1}{45}+\dfrac{1}{35}+\dfrac{1}{25}+\dfrac{1}{15}\ne0\right)\)
\(< =>x=100\)
![](https://rs.olm.vn/images/avt/0.png?1311)
(15+75)+(20+70)+(25+65)+(30+60)+(35+55)+(40+50)+45
= 90+90+90+90+90+90+45
= 90.6+45
= 540+45=585
15 + 25 + 35 + 45 + 55 = 175
k mk , mk k lại
bằng 175 nha bn
k mk nha bn
thanks nhju