(7) A Hami melon weighs \( 1 \frac{1}{2} \mathrm{~kg} \), and a watermelon weighs \( 2 \frac{1}{4} \mathrm{~kg} \). (a) What fraction of the weight of the watermelon is the weight of the Hami melon?

CALCULAR-0 \( \left\{\begin{array}{l}2 x+y=454 \\ 3 x+2 y=25\end{array}\right. \)

1. \( 6(x-1)=9(x-4) \)

Solve for \( y: 3(2 y+4)=4\left(2 y-\frac{1}{2}\right) \). The solution is \( y= \) The solution is

3) \( f(n)=n^{2}+1 \); Find \( f(n-4) \)

If a triangle is a right triangle, then the triangle has one \( 90^{\circ} \) angle. \( \triangle A B C \) is a right triangle. Conclusion: \( \triangle A B C \) has one \( 90^{\circ} \) angle. Conclusion: \( \triangle A B C \) has one \( 180^{\circ} \) angle. Conclusion: \( \triangle A B C \) has one \( 0^{\circ} \) angle. Not possible: separate conclusions