[tex]AB= \sqrt{ ( x_{b}- x_{a}) ^{2}+ ( y_{b}- y_{a}) ^{2} } } = \sqrt{16+ (m+2)^{2} }=5 [/tex]. Ridicam la patrat ambi membri , reducem 25-16=9 si obtinem ecuatia:
[tex] (m+2)^{2} =9 [/tex], de unde odata m+2=3 deci m=1 si m+2=-3 ,a doua solutie m= - 5. Deci m∈{ -5; 1}.
