Polynomials and power series. How to prove $\frac{1-x^{11}}{1-x}=1+x+x^2+x^3+\cdots+x^{10}$

Question

How do I prove that $$\dfrac{1-x^{11}}{1-x}=1+x+x^2+x^3+\cdots+x^{10} $$

Attempt: By observing first let assume that $∣x∣<1$ then $\dfrac{1-x^{11}}{1-x}=\dfrac{1}{1-x}(1-x^{11})=(1+x+x^2+x^3+x^4+\cdots +x^n +\cdots)(1-x^{11})$

Any idea or hint?