A two digit number is such that the product of its digit 20.if 9 is added to the number the digits interchanging thier places. find the number
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let digit number be x and y
A.T.Q
xy=20......(1)
so number will be
10x+y
10x+y+9=10y+x
9x-9x=(-9)
x-y=(-1)
-y=(-1)-x
y=1+x.......(2)
putting (2) in (1)
x(1+x)=20
x+x²=20
x²+x-20
x²+5x-4x-20
x(x+5)-4(x+5)
(x-4)(x+5)
x=4 : x=(-5)(rejected)
so we got our x
if x=4
y=1+4
y=5
then the number is
10(4)+5=45
I hope it works.
if like it then mark barinest.
A.T.Q
xy=20......(1)
so number will be
10x+y
10x+y+9=10y+x
9x-9x=(-9)
x-y=(-1)
-y=(-1)-x
y=1+x.......(2)
putting (2) in (1)
x(1+x)=20
x+x²=20
x²+x-20
x²+5x-4x-20
x(x+5)-4(x+5)
(x-4)(x+5)
x=4 : x=(-5)(rejected)
so we got our x
if x=4
y=1+4
y=5
then the number is
10(4)+5=45
I hope it works.
if like it then mark barinest.
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