For the first part :
1200( 1 + .05/12)^(7 *12) ≈ $1701.64 [ you are correct !!! ]
For the second part
2000 = 1200 (1 + .05/12) ^ (t * 12) divide both sides by 1200
5/3 = (1 + .05/12) ^ (t * 12) take the log of both sides
log (5/3) = log (1 + .05/12) ^ (t * 12) and by a log property, we can write
log (5/3) = (12 * t) log (1 + .05/12) divide both sides by 12log ((1 + .05/12)
log (5/3) / [ 12 log ( 1 + .05/12) ] = t ≈ 10.24 years
