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3 votes
What number multiplies to 12 but adds to 16

User LambergaR
by
8.0k points

2 Answers

2 votes
An answer would be 2
2+2+2+2+2+2=12
2*2*2*2=16

Another answer would be 4.
4+4+4=12
4*4=16
User Chris Mowforth
by
8.7k points
6 votes

x+y=16

xy=12


x+y=16

subtract x from both side

y=16-x

subsitute for y

x(16-x)=12

16x-x^2=12

subtract add x^2 to both sides

16x=12+x^2

subtract 16x from both sides

x^2-16x+12=0

try and factor

can't

use quadratic equation which is

x=
\frac{-b+/- \sqrt{b^(2)-4ac} }{2a} when you have
ax^2+bx+c=0
x^2-16x+12=0
a=1
b=-16
c=12
subsitute
x=
\frac{-(-16)+/- \sqrt{(-16)^(2)-4(1)(12)} }{2(1)}
x=
(16+/- √(256-48) )/(2)
x=
(16+/- √(208) )/(2)
x=
(16+/- 4√(13) )/(2)
x=
8+/- 2√(13)
x=
8- 2√(13) or
8+ 2√(13)
the answer is
the numbers are
8- 2√(13) and
8+ 2√(13) or
aprox 0.788897 and 15.2111
User Goul
by
8.5k points

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