3x+4y=-3 x+2y-5
2 Answers
embizze | High School Teacher | (Level 2) Educator Emeritus
Solve the system :
3x+4y=-3
x+2y=-5
We can solve using the combinations method:
Multiply the second equation by -2, then add the resulting equation to the first equation:
3x+4y=-3
-2x-4y=10
------------
x=7
Substituting x=7 into the first equation we get:
3(7)+4y=-3
4y=-24
y=-6
-----------------------------------------------------------------
The solution is (7,-6)
------------------------------------------------------------------
Check: 3(7)+4(-6)=21-24=-3 and 7+2(-6)=7-12=-5
The graphs:
tonys538 | Student, Undergraduate | (Level 1) Valedictorian
The system of equations 3x+4y=-3 and x+2y=-5 has to be solved.
From the equation x+2y=-5, express x in terms of y.
x+2y=-5
x = -5 - 2y
Now substitute this for x in 3x+4y=-3
3*(-5 - 2y) + 4y = -3
-15 - 6y + 4y = -3
-2y = 12
y = -6
x = -5 - 2y = -5 - (-6*2) = -5 + 12 = 7
The solution of the given system of equations is x = 7 and y = -6