Economics is concerned with studying and influencing the economy. Politics is the theory and practice of influencing people through the exercise of power, e.g. governments, elections and political parties.
In theory, economics could be non-political. An ideal economist should ignore any political bias or prejudice to give neutral unbiased information and recommendations on how to improve the economic performance of a country. Elected politicians could then weigh up this economic information and decide.
In practise there is a strong relationship between economics and politics because the performance of the economy is one of the key political battlegrounds. Many economic issues are inherently political because they lend themselves to different opinions.