The product of the digits of a two digit number is 24. If it's units digit exceeds twice it's ten digit by 2.find the number
Answers
unit digit=y
2x+2=y
(2x+2)x=24
2x^2 + 2x -24=0
x^2 + x - 12=0
(x-3)(x+4)=0
x=3
y number=2(3)+2=8
Number=30+8=38
Step-by-step explanation:
Let , unit digit = x and Tens digit = y , So our number will be = 10 y + x
From first condition we get
xy = 24 , So
y = 24/x --- ( 1 )
And , from second condition we get
x = 2 y + 2 , Substitute value from equation 1 and get
⇒x = 2 ( 24x ) + 2
⇒x = 48 + 2 x/x
⇒x 2 = 48 + 2 x
⇒x2 - 2 x - 48 = 0 , Now we use splitting the middle therm method and get
⇒ x2 - 8 x + 6 x - 48 = 0
⇒x ( x - 8 ) + 6 ( x - 8 ) = 0
⇒( x + 6 ) ( x - 8 ) = 0 , So
x = - 6 and 8 , But we assume x as our unit digit of two digit number and one digit can't be negative , So we neglect x = - 6 and get
x = 8 , Substitute that value in equation 1 and get
y = 248 = 3
Therefore,
Our number = 10 ( 3 ) + 8 = 30 + 8 = 38 ( Ans )