{x,y} = {-2,3}
[1] 2x + 4y = 8
[2] x - 3y = -11
4y + 2x = 8
-3y + x = -11
Solve equation for the variable x
[2] x = 3y - 11
Plug this in for variable x in equation [1]
[1] 2•(3y-11) + 4y = 8
[1] 10y = 30
Solve equation [1] for the variable y
[1] 10y = 30
[1] y = 3
By now we know this much :
x = 3y-11
y = 3
Use the y value to solve for x
x = 3(3)-11 = -2
Solution :
{x,y} = {-2,3}
<h2 />~Savannah
Solution:
Let x represent a number of calling minutes. According to the problem, we want:
now, putting the similar terms together, we obtain:
this is equivalent to:
now, solving for x, we get:
then, the correct answer for the first question is:
400 minutes is the number of minutes the two plans cost the same
now, for the second question, we can replace the above value (400 minutes) into the following equation:
so that, the correct answer for the second question is:
$55 is the cost when the two plans cost the same