Question

Pe axa numerelor ,cu originea O(0),folosind unitatea de masura 1 cm ,reprezentati punctele A(x) si B(-x),x€N*.Aflati numarul x in fiecare dintre situatile: a)AB+3×OB=15 cm b)2×OA+5×OB=21 cm.

Answer 1

$\it A(x)\ \c{s}i\ B(-x)\ sunt\ puncte\ simetrice\ fa\c{\it t}\breve{a}\ de\ O.\\ \\ OA=OB=x,\ \ AB=2x\\ \\  a)\ \ AB+3\cdot OB=15 \Rightarrow 2x+3x=15 \Rightarrow 5x=15 \Rightarrow x=3\\ \\ b)\ \ 2\cdot OA+5\cdot OB=21 \Rightarrow 2x+5x=21 \Rightarrow 7x=21 \Rightarrow x=3$