Answer: The father is 37 years and the son is 7 years
Step-by-step explanation:
Let x represent the present age of the father.
Let y represent the present age of the son.
Three years hence a father will four times as old as his son will be. This means that
x + 3 = 4(y + 3)
x + 3 = 4y + 12
x - 4y = 12 - 3
x - 4y = 9- - - - - - - - - - - - - - - -1
Before two years he was seven times as old as his son was. This means that
(x - 2) = 7(y - 2)
x - 2 = 7y - 14
x - 7y = - 14 + 2
x - 7y = - 12- - - - - - - - - - - - - - -2
Subtracting equation 2 from equation 1, it becomes
3y = 21
y = 21.3 = 7
Substituting y = 7 into equation 1, it becomes
x - 4 × 7 = 9
x - 28 = 9
x = 9 + 28
x = 37
Answer:
the money spent by a buyer to purchase a product
Answer:
domain: x>3/5
Step-by-step explanation:
First we need to derive our function g(x) to get a new function g'(x)
To do this we will have to apply chain rule because we have an inner and outer functions.
Our G(x) = square root(3-5x)
Chain rule formula states that: d/dx(g(f(x)) = g'(f(x))f'(x)
where d/dx(g(f(x)) = g'(x)
g(x) is the outer function which is x^1/2
f(x) is our inner function which is 3-5x
therefore f'(x)= 1/2x^(-1/2) and f'(x) = -5
g'(f(x)) = -1/2(3-5x)^(-1/2)
Applying chain rule then g'(x) = 1/2 (3-5x)^(-/1/2)*(-5)
But the domain is the values of x where the function g'(x) is not defined
In this case it will be 3-5x > 0, because 3-5x is a denominator and anything divide by zero is infinity/undefined
which gives us x >3/5
