Question

Plsss help to solve each system of equation(a)graphically and (b) by using any algebraic method..this is a topic of system of linear equations. here`s the equations:
{x-2y=8 and
{x+5y=-10

Solution: (x,y)=____

Answer 1

To solve it graphically, graph each equation and see where the lines intersect, like this:
http://www.wolframalpha.com/input/?i=x-2y%3D8%2Cx%2B5y%3D-10

To solve algebraically, one method is to take one equation and solve for one of the variables, then we can plug it into the other, like this:
x-2y = 8
x = 8+2y, so in the other equation,
x+5y=-10
(8+2y)+5y=-10
8+7y=-10
7y=-18
y=-18/7.
To find x, we can use one of those equations, or the x = 8+2y equation we found along the way:
x = 8+2(-18/7)
x = 20/7.
So your solution ends up being (20/7, -18/7).

Answer 2

so is this the final answer or is there an alternative solution?

Answer 3

There's only one answer, but we could have used a different algebraic method. For example, we could subtract the equations:
x-2y = 8
-(x+5y) = -(-10)
--------------
-7y = 18
y = -18/7, and so on to find x. Both get you to the same answer, so use whichever you're more comfortable with.

Answer 4

ahhh okay..thats what im thinking if i`ll use elimination by subtraction..:-D
but anyway thanks for the answer and for the effort to solve this probs..God Bless u

Answer 5

Happy to help! Good luck!