At which root does the graph of f(x) = (x – 5)3(x + 2)2 touch the x-axis?

The way you can tell if the graph is going to cross the x-axis or just touch the x-axis is by looking at the power of factor

(x-5)^3 has a power of 3 which is an ODD number. An ODD power means that the graph will cross through the x-axis

(x+2)^2 has the power of 2 which is an EVEN number. An Even power means that the graph will touch the x-axis

To find where it will touch the axis set the factor equal to zero and solve .

(x + 2) = 0

Subtract 2 from both sides

x=-2

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places

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step-by-step explanation: