Solve the system of equations using any method.
4x + y = 109
3x - y = 17
2007-07-12 08:25:03 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Add the 2 equations.
4x + y = 109 (1)
+ 3x - y = 17 (2)
_____________________
7x = 126 (3)
Divide equation (3) by 7 to get x.
x = 18
Substitute the value of x in equation (1)
4 (18) + y = 109
72 + y = 109
y = 109 - 72
y = 37
2007-07-12 08:56:35 · answer #1 · answered by g2hn 3 · 0⤊ 0⤋
elimination by addition method
4x + y = 109- - - - - - -Equation 1
3x - y = 17- - - - - - - --Equation 2
- - - - - - - - --
7x = 126
Divide both sides of the equatio by 7
7x / 7 = 126 / 7
x = 126/7
x = 18
Insert the x value into equation 1
- - - - - - - - -
4x + y = 109
4(18) + y = 108
72 + y = 109
Transpose 72
72 + y - 72 = 109 - 72
y = 37
Insert the y value into equation 1
- - - - - - - -- -
Check for equatio 1
4x + y = 109
4(18) + 37 = 109
72 + 37 = 109
109 = 109
- - - - - - - --
Cjheck for equation 2
3x +- y = 17
3(18) - 37 = 17
54 - 37 = 17
17 = 17
- - - - - - - - --
Both equations balance
The solution set is { 18, 37 }
- - - - - - - -s-
2007-07-12 16:55:03 · answer #2 · answered by SAMUEL D 7 · 0⤊ 0⤋
Simultaneous linear equations - just add the two and you get this...
7x = 126
And solve from there.
The procedure for simul. linear equations is to eliminate varibles (usually by addition or subtraction), and then solve for the one remaining variable. Then plug that solution back into the other equation(s) and solve them...
That get you started?
Ron.
2007-07-12 15:31:47 · answer #3 · answered by Anonymous · 0⤊ 0⤋
4x+y=109
3x-y=17
7x=126
3x-y=17
x=18
3(18)-y=17
x=18
54-y=17
x=18
y=37
2007-07-12 16:35:38 · answer #4 · answered by God_Of_War 2 · 0⤊ 0⤋