# The difference between two positive numbers is 7 and the square of their sum is 289. find the two numbers

2
by Wazowski

2016-01-17T15:04:41+08:00
A-b=7
a+b=c
c^2=289
c=17
12-5=7
12+5=17
17^2=289
so the two numbers are 12 and 5
• Brainly User
2016-01-17T16:15:18+08:00
The problem is involves quadratic equation.

x =  larger positive integer
y = smaller positive integer

x - y = 7        (the difference between two positive numbers)
- y =  7 - x
y = x - 7
y = x - 7 (smaller positive number in terms of x)

[x + (x-7)]² = 289     (the square of the sum of the two numbers)

(2x - 7)² = 289

4x² - 14x - 14x + 49 = 289

4x² -28x + 49 - 289 = 0

4x² - 28x - 240 = 0

4 (x² - 7x - 60) = 0

Factor x² -7x - 60:
(x - 12) (x + 5) = 0

x - 12 = 0
x = 12

x + 5 = 0
x = -5

Choose the positive value, x = 12.

Substitute 12 to x:
Larger number: x = 12
Smaller number : x-7 = 12 - 7 = 5

ANSWER: The numbers are 12 and 5.

Check:
The difference of two positive numbers is 7.
12 - 5 = 7
7 = 7  (true)

The square of their sum is 289.
(12 + 5)² = 289
(17)² = 289
289 = 289  (true)