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What are two numbers that multiply together to give -30 and add together to give -1

1 Answer

2 votes

Answer:

-6 and 5

Explanation:

Let x represent the first number, and let y represent the second

x and y multiply together to equal -30, so the equation for this is

xy=-30

x and y add to equal -1, and the equation for this is

x+y=-1

This is a system of equations

xy=-30

x+y=-1

Solve through the substitution method

Lets solve for x in the second equation

x=-y-1

Now substitute -y-1 in for x in the first equation

(-y-1)y=-30

Solve

-y^2-y=-30

Factor

(y + 6)(y - 5) = 0

Set each factor equal to 0 and solve

y+6=0, y=-6

y-5=0, y=5

Put each number in for y in one of the equations

-6x=-30

x=5

One answer is x=5, y=-6

5x=-30

x=-6

Another answer is x=-6, y=5

Since these answers contain the same numbers the answer is still -6 and 5.

You can also solve this by trial and error.

User Malasorte
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