Answer:
6 is from the beginning. Multiply first, not add
Step-by-step explanation:
k=13
19 + 12k = –k − 20
19+20=39=13k
90 degree angle.
Right triangles must have a 90 degree angle or it is not a right triangle.
![\left[\begin{array}{cc}1&1\\2&-3\end{array}\right] \left[\begin{array}{c}x\\y\end{array}\right] = \left[\begin{array}{c}4\\3\end{array}\right]](https://tex.z-dn.net/?f=%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D1%261%5C%5C2%26-3%5Cend%7Barray%7D%5Cright%5D%20%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Dx%5C%5Cy%5Cend%7Barray%7D%5Cright%5D%20%3D%20%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D4%5C%5C3%5Cend%7Barray%7D%5Cright%5D%20)