Electricity company charges customers a base rate of $10 a month, plus 6 cents per kWh for the first 1200 kWh and 7 cents per kWh for all usage over 1200 kWh. Express the monthly cost amount of electricity used.

My understanding is as below, but not sure if it is correct. Please help!

Let C as monthly cost, x as electricity usage.

C(x)=↗ 10+0.06x if x<=1200

........↘ 10+0.06x+0.07(x-1200) if x>1200