tolong dibantu ya soal dari no 4 dan 5

4).
[tex] \left[\begin{array}{ccc}3a&2\\4&-5b\\\end{array}\right] = \left[\begin{array}{ccc}a+8&2\\4&30\\\end{array}\right] \\ \\ 3a=a+8 \\ 3a-a=8 \\ 2a=8 \\ a=4 \\ \\ -5b=30 \\ b= \frac{30}{-5} \\ b=-6[/tex]


5).
[tex]2 \left[\begin{array}{ccc}2&1\\3&-1\\\end{array}\right] -\left[\begin{array}{ccc}3&-2\\-1&4\\\end{array}\right] \\ \\ \\ = \left[\begin{array}{ccc}4&2\\6&-2\\\end{array}\right]-\left[\begin{array}{ccc}3&-2\\-1&4\\\end{array}\right] \\ \\ \\ =\left[\begin{array}{ccc}1&4\\7&-6\\\end{array}\right][/tex]