If the product of two consecutive numbers is 72 then the smaller numbe

1.	If the product of two consecutive numbers is 72 then the smaller number is ………………..A) -3/2 or 19 B) -4 or 6 C) -8 or 6 D) 8 or -9
Answer» Correct option is (D) 8 or -9 Let consecutive numbers are x and x+1. \(\therefore\) x(x+1) = 72 (Given) \(\Rightarrow\) \(x^2+x-72=0\) \(\Rightarrow\) \(x^2+9x-8x-72=0\) \(\Rightarrow\) x(x+9) - 8(x+9) = 0 \(\Rightarrow\) (x-8) (x+9) = 0 \(\Rightarrow\) x - 8 = 0 or x+9 = 0 \(\Rightarrow\) x = 8 or x = -9. Correct option is D) 8 or -9

If the product of two consecutive numbers is 72 then the smaller number is ………………..A) -3/2 or 19 B) -4 or 6 C) -8 or 6 D) 8 or -9

Answer»

Correct option is (D) 8 or -9

Let consecutive numbers are x and x+1.

\(\therefore\) x(x+1) = 72 (Given)

\(\Rightarrow\) \(x^2+x-72=0\)

\(\Rightarrow\) \(x^2+9x-8x-72=0\)

\(\Rightarrow\) x(x+9) - 8(x+9) = 0

\(\Rightarrow\) (x-8) (x+9) = 0

\(\Rightarrow\) x - 8 = 0 or x+9 = 0

\(\Rightarrow\) x = 8 or x = -9.

Correct option is D) 8 or -9