Final answer:
The direct proportion between y and (x + 1) is expressed by the equation y = 0.2(x + 1). When x equals 3, y is 0.8, and when y equals 3, x is 14.
Step-by-step explanation:
Given that y is directly proportional to (x + 1) and y=2 when x=9, we can determine the constant of proportionality. First, we plug x=9 into the expression for y, which gives us 2 = k(9 + 1), where k is the constant of proportionality. Solving this equation gives us k = 0.2. Therefore, the equation expressing y in terms of x is y = 0.2(x + 1).
To find the value of y when x=3, we substitute 3 into our equation: y = 0.2(3 + 1), which simplifies to y = 0.2(4), hence y = 0.8.
To find the value of x when y=3, we set up the equation 3 = 0.2(x + 1). Solving for x, we get 3 = 0.2x + 0.2, which simplifies to 2.8 = 0.2x. Therefore, x = 14.