Answer:
$66
Step-by-step explanation:
It can be convenient to assign a different variable to the amount of money each spent. We can call the amounts spent by Seedevi, Georgia, and Amy "s", "g", and "a", respectively.
The problem statement tells us ...
s = (1/2)g
s = a +6
s + g + a = 258
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The problem statement asks for the amount Seedevi spent, so we need to find the value of s. It is convenient to write the other variables in terms of s:
g = 2s
a = s -6
Then the sum is ...
s + (2s) +(s -6) = 258
4s = 264 . . . . . . . . . . . add 6, simplify
s = 66 . . . . . . . . . . . . . .divide by 4
Seedevi spent $66.
The x-intercept is when y=0, so we plug that in our equation,

. +12 on both sides to get

. Divide by -8 to get
This is called the <u>Multiplication property of equality.</u>
The multiplication property of equality states that whatever you multiply on one side, you must multiply the same quantity on the other side of the equation. In this case, variable c is multiplied to both sides of the equation.