How do you solve the following system?: 2x-13y= 9 , 17 x + 2y = 6 2x13y=9,17x+2y=6

2 Answers
Nov 12, 2017

(32/75, -47/75)(3275,4775)

Explanation:

In solving systems of linear equations, you can use the elimination method, substitution method or graphing. Using any of these three methods would yield the same answer so it is up to you to choose which method you are most comfortable with. However in this case, I would show the elimination method.

*graphing will not be done since it is difficult to show graphs using this medium and since it is difficult to determine the exact solutions if the values are not whole numbers.

So in this case, you are given:
2x - 13y = 92x13y=9
17x + 2y = 617x+2y=6

Elimination Method
2x - 13y = 92x13y=9
17x + 2y = 617x+2y=6

You can either multiply the first equation by 17 and the second by 2 in order to eliminate xx or you can multiply 2 to the first equation and 13 to the second to eliminate yy. For this I will choose the second method since the numbers would be smaller.

2(2x - 13y) = 2(9)2(2x13y)=2(9)
13(17x + 2y) = 13(6)13(17x+2y)=13(6)

Therefore
4x - 26y = 184x26y=18
221x + 26y = 78221x+26y=78

Adding the two equations to eliminate yy would lead you to this.
225x = 96225x=96
x = 96/225x=96225
x = 32/75x=3275

Using the value of xx to obtain yy...
2(32/75) - 13y = 92(3275)13y=9
64/75 - 13y = 9647513y=9
64/75 - 9 = 13y64759=13y
-611/75 = 13y61175=13y
13y = -611/7513y=61175
y = -611/75 * 1/13y=61175113
y = -47/75y=4775

(32/75, -47/75)(3275,4775)

Nov 12, 2017

x=32/75x=3275 and y=-47/75y=4775

Explanation:

You have two equations:

A: 2x-13y=92x13y=9
B: 17x+2y=617x+2y=6

Use equation A to find the value of xx with respect to yy:

A: 2x-13y=9 rightarrow 2x=9+13y rightarrow x=(9+13y)/22x13y=92x=9+13yx=9+13y2

Then use this value in equation B to replace xx:

B: 17x+2y=17 cdot (9+13y)/2+(4y)/2=(153+225y)/2=617x+2y=179+13y2+4y2=153+225y2=6
rightarrow y=(12-153)/225=-141/225=-47/75y=12153225=141225=4775

Finaly, use this value of yy to find xx:

x=(9+13y)/2=(9+13 cdot (-47/75))/2=(9-611/75)/2=(64/75)/2=32/75x=9+13y2=9+13(4775)2=9611752=64752=3275