Question

Solve the systems using substitution. 1.6x + 2y = -2 4x + y = 1

Answer 1

$\begin{array}{ccc}(1)\\(2)\end{array}\ \left\{\begin{array}{ccc}6x+2y=-2\\4x+y=1\end{array}\right\\\\4x+y=1\ \ \ |subtract\ 4x\ from\ both\ sides\\y=1-4x\\\\subtitute\ y=1-4x\ to\ (1):\\\\6x+2(1-4x)=-2\\6x+2\cdot1+2\cdot(-4x)=-2\\6x+2-8x=-2\\-2x+2=-2\ \ \ \ |subtract\ 2\ from\ both\ sides\\-2x=-4\ \ \ |divide\ both\ sides\ by\ (-2)\\\boxed{x=2}\\\\subtitute\ the\ value\ of\ x\ to\ the\ y=1-4x:\\\\y=1-4\cdot2\\y=1-8\\\boxed{y=-7}\\\\Answer: \left\{\begin{array}{ccc}x=2\\y=-7\end{array}\right$