Concept:
The distance of the origin (0,0,0) from the plane ax+by+cz+d=0 is given by |‌

(a)(0)+(b)(0)+(c)(0)+d

√a2+b2+c2

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Calculation:
We know that the distance of the origin (0,0,0) from the plane ax+by+cz+d=0 is given by |‌

(a)(0)+(b)(0)+(c)(0)+d

√a2+b2+c2

|
⇒ The distance of the origin from the plane 2x+6y−3z+7=0
=|‌

(2)(0)+(6)(0)+(−3)(0)+7

√22+62+(−3)2

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=|‌

7

√49

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=1