How do you solve the system of equations 3x + 4y = 23 and 4x - 3y = 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 = 69
now multiply second equation by 4
we get 16x - 12y = 56
add both the obtained equations
we get 25x = 125
hence x = 5
now put x = 4 in one of the equations to get y's value
hence y = 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=23
4x−3y=14

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

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

4x−3y=14 //*(-4)

9x=12y=69
16x-12y=56

"Now we add those two equations"

25x=125 //:5
x=5

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

y=2 and x=5.

Explanation:

A way of solving the system is the following:

1- Isolate x for both equations:

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

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

(23-4y)/3 = (14+3y)/4

3- Solver this equation for y by turning everything into 4 fractions and separating fractions with y from independent fractions. y should be equal to 2

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

x=(23-4y)/3

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

Hope this was helpful and good luck with algebra!