Question

4 years before age of mother was 3 times the age of her daughter write a linear equation to represent this situation

Answer 1

Answer:

3x – y – 8 = 0

Step-by-step explanation:

Let the present age of the daughter be x years and present age of mother be y years

4 years before, age of the daughter = (x – 4) years

4 years before, age of the mother = (y – 4) years

Therefore, (y – 4) = 3(x – 4)

⇒ y – 4 = 3x – 12

∴ 3x – y – 8 = 0

Answer 2

et the current age of the daughter be x

Let the current age of the mother be y

For years ago, their ages were x-4 and y-4

y-4=3(x-4)

That's the equation of a line in point-slope form. Its slope is 3, and it passes through the nonsensical point that indicates they are both 4 now and 4 years ago they were both zero years old and of course zero equals three times zero. There are many other points that do not make sense, but let's graph anyway.

We have that nonsense point and we could pick a more sensible one, (29, 79) for the case where four years ago the mother and daughter were 25 and 75 respectively.

graph (above)