You said that. 2x - 9 = 7 . . . . .
Add. 9. to each side: 2x = 16 . . . . .
Divide each side by 2 : x = 8
404,991
PEMDAS
Multiplication comes before subtraction
900x450=405,000
405,000-9=404,991
Answer:
It will take nine years and four months for the refrigerator to pay for itself.
Step-by-step explanation:
The new refrigerator which costs $1200, saves the family 22% annually in energy cost.
Since the old refrigerator costs $580 to run, we want to determine how many years it will take for 22% of $580 per year to make $1200.
22% of $580
= 580 × 0.22
= 127.6
That is, it saved then $127.6 per year.
Now,
$1200/127.6
≈ 9.4
Which means, it will take 9 years and 4 months for the refrigerator to pay for itself.
Answer:
x = 5, y = -1/2
Step-by-step explanation:
3.5x - 5y = 20
3x + 4y = 13 multiply by 1.25 so the y's match up (you could match x's too)
3.75x + 5y = 16.25
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3.5x - 5y = 20
3.75x +5y = 16.25
7.25x + 0y = 36.25 you can add or subtract here (on this equation you add)
7.25x=36.25
x=5 So now we have x=5 and to find y we can just plug in x into one of the equations
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3(5) + 4y = 13
15 + 4y = 13
4y = -2
y = -1/2
x = 5, y = -1/2
Then you can plug in both to check your answers.
