Use an inverse matrix to solve system of linear equations.x+2y=10x-2y=-6

Find a least squares solution of Ax=b by constructing and solving the normal equations.
${\displaystyle A=\left[\begin{array}{cc}3& 1\\ 1& 1\\ 1& 4\end{array}\right],b\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right]}$
${\displaystyle \bar{x}=}$?

Solve the rational equation.
${\displaystyle \frac{7}{x}+x=\frac{88}{x}}$

First use the discriminant to determine whether the equation has two nonreal complex solutions, one real solution with a multiplicity of two, or two real solutions. Then solve the equation.
${\displaystyle 15x^2+17x-4=0}$

Solve the equation
${\displaystyle {\left(\frac{t}{t+1}\right)}^2-\frac{2t}{t+1}-8=0}$

Find an equation for the plane that contains the two lines
${\displaystyle l_1:x=t+2,y=3t-5,z=5t+1}$
and
${\displaystyle l_2:x=5-t,y=3t-10,z=9-2t}$

Solve the equation ${\displaystyle \frac{3p}{4}=6}$?

Solve the equation.
${\displaystyle \frac{9x-8}{9}+\frac{1}{x+5}=x}$