How do you solve the system of equations 3x + 4y = 233x+4y=23 and 4x - 3y = 144x3y=14?

3 Answers
Jan 17, 2018

solve the equations (as u have only 2 variables)
else solve using determinants

Explanation:

multiply first equation by 3
we get 9x + 12y = 699x+12y=69
now multiply second equation by 4
we get 16x - 12y = 5616x12y=56
add both the obtained equations
we get 25x = 12525x=125
hence x = 5x=5
now put x = 4 in one of the equations to get y's value
hence y = 2y=2
(or)
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0ahUKEwi1n4fpqd_YAhVHGZQKHU29BsoQFggzMAM&url=http%3A%2F%2Fwww.analyzemath.com%2FTutorial-System-Equations%2Fcramers_rule.html&usg=AOvVaw0WTZHPNNd0K1ISsn2SljUh
hope u find it helpful :)

Jan 17, 2018

x=5
y=2

Explanation:

3x+4y=233x+4y=23
4x−3y=144x3y=14

"First we need to get rid of either x or y"First we need to get rid of either x or y

3x+4y=23, //*33x+4y=23,/3

4x−3y=14 //*(-4)4x3y=14/(4)

9x=12y=699x=12y=69
16x-12y=5616x12y=56

"Now we add those two equations"Now we add those two equations

25x=125 //:525x=125/:5
x=5x=5

"Now we need to find y, (we can use the first equation)"Now we need to find y, (we can use the first equation)
15+4y=23 //-1515+4y=23/15
4y=8 //:44y=8/:4
y=2y=2

y=2y=2 and x=5x=5.

Explanation:

A way of solving the system is the following:

1- Isolate xx for both equations:

x=(23-4y)/3 and x=(14+3y)/4x=234y3andx=14+3y4

2- Set those two equations as equal, since they are both equivalents to xx:

(23-4y)/3 = (14+3y)/4234y3=14+3y4

3- Solver this equation for yy by turning everything into 44 fractions and separating fractions with y from independent fractions. yy should be equal to 22

4- Now that you know that y=2y=2, plug that back in an equation of xx, for example:

x=(23-4y)/3x=234y3

5- Once done that, you should get a value for xx, which is 55. Those two values are your final answer y=2 and x=5y=2andx=5

Hope this was helpful and good luck with algebra!