Mary has some trading cards. julie has 3 times as many trading cards as mary. they have 36 trading cards in all. which of these equations represents their trading card collection?

the equation that is equal to X+3X=36

Step-by-step explanation:

since they have 36 all together, we know thier total is 36. since it says that julie has three times mary, i used x to represent mary. so julie is 3x. now we know the equation x(Marie)+3x(JUlie)=36(total)

the radius is 2 times the diameter.

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