Kết quả đúng là 495

15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95

= ( 15 + 85 ) + ( 25 + 75 ) + ( 35 + 65 ) +  ( 45 + 55 ) + 95

= 100 + 100 + 100 + 100 + 95

 = 495

= ( 5 + 95 ) + ( 15 + 85 ) + ( 25 + 75 ) + ( 35 + 65 ) + ( 45 + 55 )

= 100 + 100 + 100 + 100 + 100

= 5 x 100

= 500

15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95 =495 vì 495 < 500 nên 15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95 < 500

15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95 = 495

vậy 15 + 25 + 35 + 45 + 55 + 65 + 75 + 85 + 95 < 500

1000010000803

chúc bạn học tốt~

Sai rồi họk toán vs đamê à

a) \(\left(55-27\right)+\left(27+30-55\right)\)

\(=55-27+27+30-55\)

\(=\left(55-55\right)+\left(-27+27\right)+30\)

\(=30\)

b) \(\left(75+35+15\right)-\left(15-75+35\right)\)

\(=75+35+15-15+75-35\)

\(=\left(75+75\right)+\left(35-35\right)+\left(15-15\right)\)

\(=75+75\)

\(=150\)

kế

225

625

1225

2025

3025

4225

5625

7225

9025

\(=\frac{\left(15+125\right).12:2}{14.11+14.19}\)

\(=\frac{840}{14.30}\)

\(=\frac{14.30.2}{14.30}\)

\(=2\)

\(\frac{15+25+35+...+125}{14.11+14.19}\)= \(\frac{\left(125+15\right).\left(\left(125-15\right):10+1\right):2}{14\left(11+19\right)}\)= \(\frac{140.12:2}{14.20}\)= \(\frac{840}{280}\)= 3

a) x=-2

b)x=7

c)x=11 hay -11

d)không có giá trị

e)x=85

f)x=-55

g)x=0

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