How do you solve 5x + y = -2 and 4x + 7y = 2?
1 Answer
Sep 8, 2015
Explanation:
Take a look at your system of equations
{(5x + y = -2), (4x+7y = 2) :}
Notice that if you multiply the first equation by
This will leave you with one equation with one unknown,
{(5x + y = -2 | * (-7)), (4x+7y = 2) :}
{(-35x -7y = 14), (4x+7y = 2) :}
stackrel("-----------------------------------------------")
-35x - color(red)(cancel(color(black)(7y))) + 4x + color(red)(cancel(color(black)(7y))) = 14 + 2
-31x = 16 implies x = 16/((-31)) = color(green)(-16/31)
Now use this value of
5 * (-16)/31 + y = -2
y = -2 + 80/31
y = color(green)(18/31)