For the following exercises, find the inverse of the matrix.
61. \left[\begin{array}{rr}-0.2 & 1.4 \\ 1.2 & -0.4\end{array}\right]
62. \left[\begin{array}{rr}\frac{1}{2} & -\frac{1}{2} \\ -\frac{1}{4} & \frac{3}{4}\end{array}\right]
63. \left[\begin{array}{ccc}12 & 9 & -6 \\ -1 & 3 & 2 \\ -4 & -3 & 2\end{array}\right]
64. \left[\begin{array}{lll}2 & 1 & 3 \\ 1 & 2 & 3 \\ 3 & 2 & 1\end{array}\right]
For the following exercises, find the solutions by computing the inverse of the matrix.
65.
0.3 x-0.1 y=-10
-0.1 x+0.3 y=14
66.
0.4 x-0.2 y=-0.6
-0.1 x+0.05 y=0.3
67.
\begin{array}{r}
4 x+3 y-3 z=-4.3 \\
5 x-4 y-z=-6.1 \\
x+z=-0.7
\end{array}
68
-2x - 3y _2 z=3
-x+2 y+4 z=-5
-2 y+5 z=-3
For the following exercises, write a system of equations to solve each problem. Solve the system of equations.
69. Students were asked to bring their favorite fruit to class. 90 \% of the fruits consisted of banana, apple, and oranges. If oranges were half as popular as bananas and apples were 5 \% more popular than bananas, what are the percentages of each individual fruit?
70. A sorority held a bake sale to raise money and sold brownies and chocolate chip cookies. They priced the brownies at \$ 2 and the chocolate chip cookies at \$ 1 . They raised \$ 250 and sold 175 items. How many brownies and how many cookies were sold? ?