Question

find the real numbers whose sum is 8 and whose product is 16​

Answer 1

Answer:

The number is 4.

Step-by-step 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 :

$x + y = 8 - - - (1)$

$xy = 16$

$y = \frac{16}{x} - - - (2)$

$(2)⇒(1)$

$x + \frac{16}{x} = 8$

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

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

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

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

$x = 4$

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

$4 + y = 8$

$y = 4$