7. which of the following illustrates the associative property of addition?
(1) x+10=10+x
(2) 4(x+8)=4•x+4•8
(3) x+10+5x = x+5x+10
(4) (7x+5)-2 = 7x +(5-2)

pretty sure its (3) x+10+5x = x+5x+10

Step-by-step explanation:

associative properties always involve 3 or more numbers, so I assume its 3 as its addition and it has 3 terms.

step-by-step explanation:

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