Question

Cum se fac exercitiile 1.2.3? stie cineva ?

Answer 1

2)
[ 10 + 10 x ( a - 10 ) ] : 10 = 20
 10 + 10 x ( a - 10 ) = 20 x 10
10 + 10 x ( a - 10 ) =  200
10 x ( a - 10 ) = 200 - 10 
10 x ( a - 10 ) = 190 
a - 10 = 190 : 10
a - 10 = 19 
a = 19 + 10
a = 29

Verific:  [ 10 + 10 x ( 29 - 10) ] : 10 = ( 10 + 190) : 10 = 200 : 10 = 20

4)

26 < a < 195 - 85
26 < a < 110 ⇒  a = ( 27, 28, 29,.........109)