Solving a System of Linear Equations In Exercises 3948, write the system of linear equations in the form Ax = b and solve this matrix equation for x.4x1 + 9x2 = 13 x1 3x2 = 12

Trigonometry Section 2.4 and 2.5 Cos(a-b) = cosacosb + sinasinb Cos(a+b) = cosacosb – sinasinb Sin(a-b) = sinacosb - cosasinb Sin(a+b) = sinacosb + cosasinb tana−tanb Tan(a-b) =1+tanatanb tana+tanb Tan(a+b) = 1−tanatanb Here is an example problem: 7π 7π 2π π Find the Exact value ofn12 (hint: 12= 3− 4 ) 2π π 2π π 2π π sin(3 − 4)=sin 3 cos4−cos 3 sin4 Plug in the values ¿ √3 √2 − −1 √2 ( 2 ( 2 ( 2 ( 2 Derive reference angles ¿ √6−− √ Multiply 4 4 √ √ 2 4 Combine (this is the finished form of the problem