Practice problem
Evaluate the expression 121(113−117)+169(117−111)+289(111−113)11(113−117)+13(117−111)+17(111−113)\frac{121\left(\frac{1}{13}-\frac{1}{17}\right)+169\left(\frac{1}{17}-\frac{1}{11}\right)+289\left(\frac{1}{11}-\frac{1}{13}\right)}{11\left(\frac{1}{13}-\frac{1}{17}\right)+13\left(\frac{1}{17}-\frac{1}{11}\right)+17\left(\frac{1}{11}-\frac{1}{13}\right)}11(131−171)+13(171−111)+17(111−131)121(131−171)+169(171−111)+289(111−131)
(Hint: Let a=11a = 11a=11, let b=13b = 13b=13, and let c=17c = 17c=17.)
Source: Math Prize for Girls
424242
414141
212121
171717
Type a concept, like “slope” or “photosynthesis”.
