15 Mark for Review \( \frac{x-18}{6}+\frac{y+25}{3}=-5 \) The solution to the given system of equations is \( (x, y) \). What is the value of \( x-y \) ?

Find the inverse of the bijective function \( Q F: R \rightarrow \) difined by \( f(x)=2 x+7 \)

marks. Find the maximum marks. Solve the following equation by systematic and transpositic \( \frac{x}{3}-\frac{4}{5}=\frac{(x-2)}{4} \)

Solve the equation: \( \sqrt{x + 4} = 6 \)

Solve the equation \( x: \log _{x+1}\left(x^{2}+x-6\right)^{2}=4 \) We have

9. An ice manufacturing machine requires 10 minutes to warm up before the production of ice begins. The weight, in tonnes, of ice produced varies directly as the number of hours of production. Given that 20 tonnes of ice are produced when the machine is run for half an hour, find the weight of ice manufactured when the machine is run for \( 1 \frac{3}{4} \) hours.