Question

  Classify the system and determine the number of solutions. Check all that apply. {7x + y = 13 28x + 4y = -12 A) inconsistent B)consistent C)infinitely  many solution D) no solution

Answer 1

$\left\{\begin{array}{ccc}7x+y=13&|multiply\ both\ sides\ by\ (-4)\\28x+4y=-12\end{array}\right\\+\left\{\begin{array}{ccc}-28x-4y=-52\\28x+4y=-12\end{array}\right\ \ \ |add\ the\ sides\ of\ the\ equations\\------------\\.\ \ \ \ \ \ \ \ 0=-64-FALSE\\\\Answer:A)\ inconsistent\ and\ D)\ no\ solution.$