• question_answer 21) Find the value of y in the expression, $\sqrt{1+\sqrt{1-\frac{2176}{2401}}}=1+\frac{y}{7}$ A)  1B)  5             C)  2                                D)  7

(a): $\sqrt{1+\sqrt{1-\frac{2176}{2401}}}=\sqrt{1+\sqrt{\frac{225}{2401}}}$ $=1+\sqrt{\frac{15}{45}}=\sqrt{\frac{64}{49}}=\frac{8}{7}$ $\therefore \frac{8}{7}=1+\frac{y}{7}\Rightarrow y=1$