Let the number be x According to the question, 3×x2−4×x=x+50 ⇒‌‌3x2−5x−50=0 ⇒‌‌3x2−15x+10x−50=0 ⇒‌‌3x(x−5)+10(x−5)=0 ⇒‌‌(x−5)(3x+10)=0 ⇒‌‌x=5 or ‌
−10
3
But the number is natural. ∴ Hence, required number =5