2+5√7 ————=a+b√7 2-5√7 Nilai a+b ???

2+5√7
————=a+b√7
2-5√7
Nilai a+b ???

$frac{2 + 5sqrt{7} }{2 - 5 sqrt{7} } \ = frac{(2 + 5 sqrt{7})(2 + 5 sqrt{7} ) }{(2 - 5 sqrt{7} )(2 + 5 sqrt{7}) } \ = frac{4 + 10 sqrt{7} + 10 sqrt{7} + 25 times 7 }{4 - 5 times 7} \ = frac{179 + 20 sqrt{7} }{- 31}$

a = -179/31
b = -20/31

a + b = -179/31 – 20/31 = -199/31