1.6.89 Fields, Groups, Rings

Condition: let \ (b \)- subgroup in \ (g l_ {2} (\ mathbb {r}) \), consisting of the upper wrestling matrices, a \ (u- \) subgroup B \ (b \), consisting of matrices with units on the main diagonal. Prove that \ (b / u \ cong \ mathbb {r}^{*} \ times {r}^{*} \).