What two numbers multiply to -20 then add to -8?
2 answers:
Answer:
-10 and 2
Step-by-step explanation:
1. Think about what numbers multiply to -20: -10 and 2, 10 and -2, -20 and 1, 20 and -1, 4 and -5, -4 and 5
2. Then, think about which of the above adds to -8. This leaves you with -10 and 2
Answer: 2 and -10
Step-by-step explanation:
<u>Starter:</u>
Let x be one of the two numbers
Let y be the other number
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Solve:
Given
x + y = -8
xy = -20
Simplify
x = -8 - y
xy = -20
Substitution
(-8 - y)y = -20
Expand parenthesis
-8y - y² = -20
Add 20 on both sides
-8y - y² + 20 = -20 + 20
-8y - y² + 20 = 0
Solve quadratic equation
(y - 2) (y + 10) = 0
y = 2 or y = -10
x = -8 - y
x = -8 - (2) or x = -8 - (10)
x = -10 or x = 2
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Step-by-step explanation:
To find the inverse of an equation, swap the x- and y-variables:
y = x² + 16
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Then, solve for the y-variable:
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Step-by-step explanation:
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