For what ordered pair $(a,b)$ are there infinite solutions $(x,y)$ to the system\begin{align*} 4x+ay&=-8,\\ 2x+y&=b. \end{align*}
4x + ay = - 8
2x + y = b ⇒ 4x + 2y = 2b
If a = 2 and b = -4 the equations will be identical and the system will have infinite solutions
So (a, b) = ( 2, - 4)
