Let daniel's age = d and let jessica's age = j
let your current age = x and your wife's current age = y
x = 5d (given in question)
∴ x - 5d = 0
x + 21 = 2(d+21) (given in question)
∴ x + 21 = 2d + 42
∴ x - 2d = 21
We can solve these two rearranged equations simultaneously by multiplying the first equation by -1 and adding them. This gives us the following:
3d = 21
∴ d = 7
This means that daniel is currently 7 and (if we substitute d = 7 into one of the equations) you are 35. We use a similar method for your wife's and jessica's current ages.
y = 7j (given in question)
∴ y - 7j = 0
y + 8 = 3(j + 8)
∴y + 8 = 3j + 24
∴ y - 3j = 16
If we use a similar method of elimination we get this:
4j = 16
∴ j = 4
Hence, from this we can concur that daniel is 7 and jessica is 4.
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Answer/Step-by-step explanation:</h2>
Direct variation occurs when a variable varies directly with another variable. That is, as the x-variable increases, the y-variable also increases.
The ratio of between y-variable and x-variable would be constant.
Direct variation can be represented by the equation, 
, where k is a constant. Thus,
From the table given, it seems, as x increases, y also increases. Let's find out if there is a constant of proportionality (k).
Thus, ratio of y to x, 
k = 0.5.
If the given table of values has a direct variation relationship, then, plugging in the values of any (x, y), into , should give us the same constant if proportionality.
Let's check:
When x = 2, and y = 1:
,
,
When x = 3, y = 1.5:
,
When x = 5, y = 2.50:
,
The constant of proportionality is the same. Therefore, the relationship forms a direct variation.
Answer:
When multiplying fractions together, you multiply the numerators togethers and the denominators together, unlike adding fractions together. To find this answer, you'd do 3 × 7 (for the numerator) and 8 × 9 (for the denominator), and then write the fraction (the answer) using your answers above.
I hope this helps!
-3x-2.5=y would be an equivalent to that equation
