Question

Sa se calculeze 1+(n-1)×2=19

Answer 1

1+(n-1)x2=19/-1
(n-1)x2=18/:2
n-1=9/+1
n=10

Answer 2

1+(n-1)x2=19
1+2n-2=19
-1+2n=19
2n=19+1
2n=20
n=20:2
n=10