[latex] \frac{2a}{4a ^{2}-10ab } - \frac{5b}{4a ^{2}-25b ^{2} } ; a=5. b= \sqrt{3} [/latex]

[latex] \frac{2a}{4a ^{2}-10ab } - \frac{5b}{4a ^{2}-25b ^{2} } =\frac{2a}{2a(2a-5b) } - \frac{5b}{(2a-5b)(2a+5b)} = \\ \frac{1}{(2a-5b) } - \frac{5b}{(2a-5b)(2a+5b)} = \frac{2a+5b}{(2a-5b)(2a+5b) } - \frac{5b}{(2a-5b)(2a+5b)} = \\ \frac{2a+5b-5b}{(2a-5b)(2a+5b) }= \frac{2a}{(2a-5b)(2a+5b) }= \frac{2a}{4a ^{2}-25b ^{2} } \\ \\ a=5 \\ b= \sqrt{3} \\ \frac{2*5}{4*5 ^{2}-25( \sqrt{3} )^{2} }= \frac{10}{4*25-25*3} =\frac{10}{100-75}= \frac{10}{25} =0.4[/latex]