9x²-0x-4
=9x²-4
=(3x-2)(3x+2) is the factor form of 9x²-0x-4
Solve for x:
3x-2=0
Add 2 to each side
3x-2+2=0+2
3x=2
Divided 3 to each side
3x/3=2/3
x=2/3
Or
3x+2=0
Subtract 2 to each side
3x+2-2=0-2
3x=-2
Divided 3 to each side
3x/3=-2/3
x=-2/3. Hope it help!
The assumptions of a regression model can be evaluated by plotting and analyzing the error terms.
Important assumptions in regression model analysis are
- There should be a linear and additive relationship between dependent (response) variable and independent (predictor) variable(s).
- There should be no correlation between the residual (error) terms. Absence of this phenomenon is known as auto correlation.
- The independent variables should not be correlated. Absence of this phenomenon is known as multi col-linearity.
- The error terms must have constant variance. This phenomenon is known as homoskedasticity. The presence of non-constant variance is referred to heteroskedasticity.
- The error terms must be normally distributed.
Hence we can conclude that the assumptions of a regression model can be evaluated by plotting and analyzing the error terms.
Learn more about regression model here
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Answer:
Speed of plane in still air: 490 mile/hour
speed of wind: 70 mile/hour
Step-by-step explanation:
still speed = x wind speed = w
with wind: speed = still + wind
(x+w) * 3 = 1680 ...a
against wind: speed = still - wind
(x-w) * 4 = 1680 ...b
b-a ... 4x-4w-3x-3w = 0
x-7w = 0
x = 7w
substitution: (7w+w)*3 = 1680 8w = 560 wind speed (w) = 70
still speed (x) = 7w = 490 mile/hour
Answer:
yeet
Step-by-step explanayeettion:
10
Answer:
30
Step-by-step explanation:
x = 7
( x - 4 )^2 + 3x
= ( 7 - 4 )^2 + 3 ( 7 )
= 3^2 + 21
= 9 + 21
= 30
