4. Hana, Huda, dan Joni menabung di bank. Jumlah uang tabungan Huda dan dua kali uang Joni, Rp150,000,00 lebih banyak dari uang tabungan Hana, Jumlah uang tabung- an Hadi dan Toni adalah Rp1.450.000,00. Jumlah uang tabungan mereka bertiga Rp2.000.000,00, System persamaa linear yang bisa dibentuk jika dimisalkan banyak uang Hana, Huda, dan Joani masing-masing x, y, dannzadalah ....

6) \( 30 \% \) of \( 600=\ldots(1.8,18,180,1800) \)

\[ -\quad-x_{1}+2 x_{2}-7 x_{3}=4 \] 3. (30 points) Solve the system of linear equations using Gauss-Jordan method. Find the rank of the matrix of this system. Indicate dependent and independent variables. Find the fundamental solution set (write the answer as a linear combination of particular vectors) \[ \begin{array}{l}x_{1}+3 x_{2}+2 x_{3}-3 x_{4}=0 \\ 2 x_{1}+6 x_{2}+3 x_{3}-4 x_{4}=0 \\ 3 x_{1}+9 x_{2}+4 x_{3}-5 x_{4}=0\end{array} \]

Soumik has \( \$ 5 \) less than Kofi. If they have \( \$ 97.50 \) altogether, how much does each person have?

Find all the second partial derivatives. \[ w=\sqrt{u^{7}+v^{9}} \] \( w_{u u}=42 u^{5} \) \( w_{u v}=0 \) \( w_{v u}=0 \) \( w_{v v}=72 v^{7} \)

Find the real solutions of the equation. (Enter your answers as a comma-separated list. If the solution is not (a) \( x^{3 / 5}=-8 \) \( x=\square x^{2 / 3}=16 \) (b) \( x=x^{4 / 3}=-64 \) (c) \( x=x^{2} \)