Question 1135310: What number multiplied equals -6 and adds 7
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! let a be one of the numbers and let b be the other of the numbers.
you get a * b = -6 and you get a + b = 7
in the second equation, solve for a to get a = 7 - b.
in the first equation, replace a with 7 - b to get (7 - b) * b = -6.
simplify this to get 7b - b^2 = -6
subtract 7b and add b^2 to both sides of the equation to get 0 = b^2 - 7b - 6
this is the same as b^2 - 7b - 6 = 0
factor this equation using the quadratic formula to get:
b = 7.772001873 or b = -.7720018727.
solve for a in the first equation to get:
when b = 7.772001873, a= -6 / 7.772001873 = -.7720018727.
when b = -.7728018727, a = -6 / -.7720018727 = 7.7720018727.
add them together, you get 7.
multiply them together you get -6.
so you have two possible answers.
a = -.7720018727 when b = 7.772001873
a = 7.772001873 when b = -.7720028727
your answer should be that one of the numbers is equal to 7.772001873 and the other number is -.7720028727
multiply them together, you get -6.
add them together, you get 7.
|
|
|
