Factor completely: 25x2 - 64 a) 5(x - 8)(x + 8) b) 5(x - 8)(x - 8) c) (5x - 8)(5x + 8) d) (25x - 1)(x + 64)

Rewrite it in the form a^2 - b^2, where a = 5x and b = 8

(5x)^2 - 8^2

Use the Difference of Squares; a^2 - b^2 = (a + b)(a - b)

= C. (5x - 8)(5x + 8)

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