Question

4. Sc 1. Solve by substitution 3x – 2y = 14 y=5x A. (-2,-10 B. (-2, 10) C. (2, -10) D. infinitely many solutions

Answer 1

`\begin{gathered} 3x-2y=14\ldots eqn(1) \\ y=5x\ldots eqn(2) \end{gathered}`

Substituting eqn(2) into eqn(1), we get

`\begin{gathered} 3x-2(5x)=14 \\ 3x-10x=14 \\ -7x=14 \\ \text{Dividing both sides by -7, we get} \\ x=(14)/(-7) \\ x=-2 \end{gathered}`

Substituting -2 for x in eqn(2), we get

`y=5x=5(-2)=-10`

Hence, the correct answer is (-2,-10) (option A)