Hey I'm having a hard time figuring this question out. Thanks for helping.

Consider the following model with exogenous public investment and spending.

Y = C + I + G and C = a + bYd. Disposable income Yd is equal to Y T, where T represents total taxes. Suppose that taxes are not directly linked to income so that T can be increased or decreased independently of income.

Determine Y / T (by Determining the expression of the change in Y (noted Y), associated with an increase in taxes T (noted T). Present the results algebraically.), that is, the tax multiplier.