Find the real numbers whose sum is 8 and whose product is 16

Question

asked Mar 8, 2021 192k views

1 Answer

LarrikJ · Answer 1 · 2021-03-14T04:06:59+0000

Answer:

The number is 4.

Explanation:

First, you have to form equations for the numbers. Let x be the first number and y be the second :

x + y = 8

xy = 16

Next, you have to solve the simultaneous equation by substitution method :

x + y = 8 - - - (1)

xy = 16

y = (16)/(x) - - - (2)

(2)⇒(1)

x + (16)/(x) = 8

$\frac{ {x}^(2) + 16 }{x} = 8$

${x}^(2) + 16 = 8x$

${x}^(2) - 8x + 16 = 0$

${(x - 4)}^(2) = 0$

x = 4

$substitute \: x = 4 \: into \: (1)$

4 + y = 8

y = 4