Question

Ex:11)
Vă rooooog ajutațimă

Answer 1

a)
10+x+20+x+30+x+....90+x= 459
10(1+2+3+4...+9) + 9 x =459
10 *9*10:2 + 9 x = 459
900:2 + 9x= 459
450 + 9x = 459
9x=459-450
9x=9
x=9:9
x=1

b)
x/10 + 1+ x/10 + 2+ x/10 +..+9+x/10 = 48
9*10:2+ 10 *x/10 = 48
45 + 10x/10 = 48
10x/10 = 48-45
10x/10=3
x=3

c)
3+ x/9 + 4+x/9+ 5+x/9 +..+8+x/9= 35
3+4+5+6+7+8 + 6x/9 = 35
33 + 2x/3 = 35
2x/3= 35-33
2x/3 = 2
2x=2*3
2x=6
x=6:2
x=3


d)
1x/99 + 2x/99+3x/99+4x/99= 125-1/99  /*99
1x + 2x + 3x+ 4x = 124
10+x+20+x+30+x+40+x = 124
100 + 4 x =124
4 x =124-100
4 x =24
x=24:4
x=6