Answer:
x = 1/2 or 0.5
Step-by-step explanation:
3x - 4 = x +5 (1) subtract x
2x - 4 = 5 (2) subtract 5
2x + 1 (3) divide by 2
x = 1/2 or 0.5
f(x)= 3x³ - 18x +9
Algebraic identities are algebraic equations that are true regardless of the value of each variable. Additionally, they are employed in the factorization of polynomials. Algebraic identities are employed in this manner for the computation of algebraic expressions and the solution of various polynomials.
Identity I: (a + b)² = a² + 2ab + b²
Identity II: (a – b)² = a² – 2ab + b²
Identity III: a² – b²= (a + b)(a – b)
Identity IV: (x + a)(x + b) = x² + (a + b) x + ab
Identity V: (a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ca
Identity VI: (a + b)³ = a³ + b³ + 3ab (a + b)
Identity VII: (a – b)³ = a³ – b³ – 3ab (a – b)
Identity VIII: a³ + b³ + c³ – 3abc = (a + b + c)(a² + b² + c² – ab – bc – ca)
f(x) = (3x + 6) (x - 3)²
= ( 3x + 6) ( x - 3 )²
= ( 3x + 6)( x² - 6x + 9)
= 3x( x² - 6x + 9) + 6( x² - 6x + 9)
= 3x³ - 6x² + 18x + 6x² - 36x +9
= 3x³ - 18x +9
To learn more about algebraic expansions, refer to brainly.com/question/4344214
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Answer: This coil will not be enough to complete the job.
Step-by-step explanation:
The circumference of the coil of wiring can be calculated with:

Where r is the radius and 
The radius can be calculated by dividing the diameter by 2. Then:

Convert 9 inches to yards (1 yard=36 inches):

Substitute this radius into the formula:

Since there are 21 circles of wire, you need to multiply
by 21:

The coil has 32.97 yards of wire and Alex needs 34 yards, therefore, this coil will not be enough to complete the job.
Answers:
Horizontal Line: y = 5
Vertical Line: x = 8
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Explanation:
All horizontal lines are of the form y = k, for some constant k. We want the horizontal line to pass through (8,5), meaning every point on this horizontal line must have y coordinate 5. Therefore, y = 5 is the equation of the horizontal line. Two such points on this line are (1, 5) and (8, 5). All that matters is the y coordinate is 5. The x coordinate can be anything you want. The slope of any horizontal line is 0.
Flipping things around, all vertical lines will have the x coordinate of each point be the same value. Draw a vertical line through (8,5) and note how each point has x coordinate of 8. Two such points are (8,1) and (8,5). Therefore, the equation of the vertical line is x = 8. The y coordinate can be any value you want. The slope of any vertical line is undefined. Unlike the horizontal line, we cannot write this equation in slope intercept form (namely because the slope isn't defined).