Question 27858: 4x+2y=14
7x-3y=-8
Answer by Sridi(6)   (Show Source):
You can put this solution on YOUR website! We need to eliminate one of the variables first to solve the system of equations.
either we can eliminate the x variable, solve for y first or the other way around.
Let us call
4x+2y=14 --------Equation 1
7x-3y=-8 -------- Equation 2
Now multiply the entire equation 1 by 3 and equation 2 by 2
(4x+2y=14) * 3
(7x-3y=-8) * 2
we will get
12x + 6y = 42 -------Equation 1a
14x -6y = - 16 ------- Equation 2b
Now add equation 1a and 2b
The =6y will cancel with -6y
You are left with
26x = 26
X = 26/26
X = 1
Now substitute x = 1 in equation 1
4(1) + 2y = 14
2y+4 + 14
2y = 14- 4 = 10
2y = 10
y = 5
Now check with equation 2 with x = 1 and y = 5
7(1) - 3(5) = 7 - 15 = -8.
We have proved that 7x - 3y = -8 just like equation 2 is with the values we calculated for x and y. hence x =1, and y = 5 are correct answers for the sytem of equation given.
|
|
|
