SOLUTION: A positive integer is 8 more than 15 times another. Their product is 272. Find the two integers

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Question 970199: A positive integer is 8 more than 15 times another. Their product is 272. Find the two integers
Answer by erica65404(394) About Me  (Show Source):
You can put this solution on YOUR website!
positive interger = x
other integer = y

A positive integer is 8 more than 15 times another.
x=8%2B15y
Their product is 272.
xy=272
Now use the first equation to solve for b in the second
x=8%2B15y
xy=272
%288%2B15y%29y=272
8y%2B15y%5E2=272
15y%5E2%2B8y-272=0
use the quadratic formula to find the values for y.

a=15
b=8
c=-272
%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
%28-8+%2B-+sqrt%28+8%5E2-4%2A15%2A%28-272%29+%29%29%2F%282%2A15%29+
%28-8+%2B-+sqrt%28+16384+%29%29%2F%2830%29+
%28-8+%2B-+128%29%2F30
y can be either 4 or -4.5.
But the correct value for y is 4.
the reason for this is because the first value is positive.
the product of the 2 numbers (x and y) is a positive 272. so y would have to be positive for this to be true.
to find x, use the second equation.
xy=272
x%2A4=272
x=68
x is 68 and y is 4.

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