How do you solve 9x -2y = 28 and y= -3x + 1?
1 Answer
Explanation:
Your starting system of equations looks like this
#{(9x - 2y = 28), (y = -3x + 1) :}#
Notice that you can rearrange the second equation to get the
#{(9x - 2y = 28), (3x + y = 1) :}#
Another thing to notice here is that if you multiply the second equation by
This will allow you to find the value of
#{(9x - 2y = 28), (3x + color(white)(x)y = color(white)(x)1 | xx 2) :}#
#{ (9x - 2y = 28), (6x + 2y = color(white)(x)2) :}#
Now add the two equations as described above
#{ (9x - 2y = 28), (6x + 2y = color(white)(x)2) :}#
#color(white)(x)stackrel("-------------------------------")#
#9x - color(red)(cancel(color(black)(2y))) + 6x + color(red)(cancel(color(black)(2y))) = 28 + 2#
#15x = 30 implies x = 30/15 = color(green)(2)#
Now use this value of
#3 * (color(green)(2)) + y = 1#
#y = 1 - 6 = color(green)(-5)#
The solution set for this system of equations will be
#{(x=2), (y = -5) :}#