7. The product of two numbers is 572.
The sum of the numbers is 12 times
their positive difference. What is
the larger of the two numbers?

Respuesta :

To solve this problem, we need to define the two numbers and create equations based on the given information. Let's call the two numbers [tex]\( a \)[/tex] and [tex]\( b \)[/tex], where [tex]\( a \)[/tex] is the larger number.

Given:

1. The product of two numbers is 572.
[tex]\[ a \cdot b = 572 \][/tex]

2. The sum of the numbers is 12 times their positive difference.
[tex]\[ a + b = 12 \cdot |a - b| \][/tex]

We also know that since [tex]\( a \)[/tex] is the larger number, the absolute value is not necessary since [tex]\( a - b \)[/tex] will always be positive. Therefore, we can rewrite the second equation as:

[tex]\[ a + b = 12(a - b) \][/tex]

Now let's solve the equations.

Equation 1:
[tex]\[ a \cdot b = 572 \][/tex]
[tex]\[ b = \frac{572}{a} \][/tex]

Equation 2:
[tex]\[ a + b = 12(a - b) \][/tex]
[tex]\[ a + \frac{572}{a} = 12a - 12\frac{572}{a} \][/tex]

To eliminate the fraction, multiply through by [tex]\( a \)[/tex]:

[tex]\[ a^2 + 572 = 12a^2 - 6876 \][/tex]

Reorder terms and combine like terms:

[tex]\[ 11a^2 - a^2 = 6876 + 572 \][/tex]
[tex]\[ 11a^2 - a^2 = 7448 \][/tex]
[tex]\[ 10a^2 = 7448 \][/tex]
[tex]\[ a^2 = \frac{7448}{10} \][/tex]
[tex]\[ a^2 = 744.8 \][/tex]

Since [tex]\( a \)[/tex] is a real number, we take the square root of both sides:

[tex]\[ a = \pm\sqrt{744.8} \][/tex]

However, we are looking for the larger number which must be positive:

[tex]\[ a = \sqrt{744.8} \][/tex]

The square root is slightly below [tex]\( \sqrt{729} = 27 \)[/tex] and we are looking for integers since the product of the numbers is an integer and the sum also suggests they should be integers. Therefore, the closest integer is [tex]\( a = 26 \)[/tex]. But we must verify if [tex]\( b \)[/tex], the smaller number, is also an integer.

[tex]\[ b = \frac{572}{a} \][/tex]
[tex]\[ b = \frac{572}{26} \][/tex]
[tex]\[ b = 22 \][/tex]

So the two numbers that satisfy both conditions are 26 and 22. Since [tex]\( a \)[/tex] is the larger number:

The larger of the two numbers is 26.