Solve -4(3x – 7) = 40 for x.
1 answer:
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9514 1404 393
Answer:
B. 3
Step-by-step explanation:
If all you want is a numerical result, sometimes a graphing calculator can provide that easily. The attachment shows it calculates the slope at x=4 to be 3.
dy/dx = 3 at x = 4
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The derivative of the expression can be found from the quotient formula:
d(u/v) = (du·v -u·dv)/v²
y' = ((x -2)(2x -7) -(x^2 -7x +2)(1))/(x -2)^2
= (2x^2 -11x +14 -x^2 +7x -2)/(x -2)^2
= (x^2 -4x +12)/(x -2)^2
= ((x -4)x +12)/(x -2)^2
Then for x=4, we have ...
y' = 12/4 = 3
dy/dx = 3 at x = 4
