help me solve this in algebra form?

Question

Martha wants to buy a digital camera from her three-month savings. To do this she needs to maintain an average saving of $300 in each month. She saves $450 in the first month and $200 in the second month. Find the amount she should save in the third month to buy a digital camera at the end of three months

Answer 1

450 + 200 + x / 3 = 300
450 + 200 + x = 300 * 3
650 + x = 900
x = 250

Answer 2

The total amount that Martha needs to save over three months is:

3*300 = $900

The amount remaining to be saved in the third month is:

900 - 450 - 200 = 900 - 650 = $250

She needs to save $250 in the third month.

Answer 3

The amount she needs to buy the camera:
$300 * 3 = $900

The amount she should save in the 3rd month to buy the camera:
$900 - ($450 + $200)
$900 - $650
$250

Answer: $250 the savings she needs on the 3rd month to buy the camera.

Answer 4

$450 +$200 + $x = $300 x3
650 + x =900
650 + x - 650 = 900 - 650
x = 250

She needs to save $250 on the 3rd month

Answer 5

3 months average of $300 = 3* 300=900$

450(1st month)+ 200(2nd month)+ X=900

X=900-(450+200)=$250

she needs to save $250 in the third month to buy her camera

Answer 6

let the first month = w the second = x and the third = y and the total amount z (z=300*3)

y = z - x - w
= (300*3) - 450 - 200
= 900 - 650
= 250

ta da!!

Answer 7

900=450+200+x
900=650+x
250=x

she would have to save 250$ the last month

Answer 8

$250