Answer:
fourth number is 9
Step-by-step explanation:
let 'x' equal the fourth number
(5+7+7+x)/4 = 7
cross-multiply to get:
19 + x = 28
x = 9
Answer:
√75, 9, 9.5, √99, 10
Step-by-step explanation:
that's what I got
Answer:
y = - 10
Step-by-step explanation:
Given that y varies directly with x then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 2 when x = - 4, that is
2 = - 4k ( divide both sides by - 4 )
= k, that is
k = -
y = - x ← equation of variation
When x = 20, then
y = - × 20 = - 10
X + y = 2 —> y = 2 - x
insert to first equation
2-x=x^2-3x-6
x^2 - 3x - 6 - 2 + x = 0
x^2 - 2x - 8 = 0
(x-4)(x+2) = 0
x = 4 or x = -2
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