Question

Can you help me with this equation -3y = -3x + 3 -4y = x - 20

Answer 1

`\huge\boxed{x=(24)/(5),\ y=(19)/(5)}`

Explanation:

`\left\{\begin{array}{ccc}-3y=-3x+3&\text{divide both sides by (-3)}\\-4y=x-20\end{array}\right\\\\\left\{\begin{array}{ccc}y=x-1&(1)\\-4y=x-20&(2)\end{array}\right\\\\\\\text{Substitute (1) to (2):}\\\\-4(x-1)=x-20\qquad\text{use the distributive property}:\ a(b+c)=ab+ac\\\\(-4)(x)+(-4)(-1)=x-20\\\\-4x+4=x-20\qquad\text{subtract 4 from both sides}\\\\-4x=x-24\qquad\text{subtract}\ x\ \text{from both sides}\\\\-5x=-24\qquad\text{divide both sides by (-5)}\\\\x=(24)/(5)`

`\text{Put it to (1)}:\\\\y=(24)/(5)-1\\\\y=(24)/(5)-(5)/(5)\\\\y=(24-5)/(5)\\\\y=(19)/(5)`