plz help with systems
For certain values of k and m, the system
3a + 2b = 2
6a + 2b = k + 3a + mb
has infinitely many solutions (a,b). What are k and m?
To find the values of k and m that make the system have infinitely many solutions, we need to find conditions under which the two equations are equivalent. In other words, we want to find values of k and m such that the second equation can be obtained from the first equation by multiplying both sides by a constant and adding a constant.
Let's subtract the first equation from the second equation:
(6a + 2b) - (3a + 2b) = k + 3a + mb - 2
Simplifying, we get:
3a = k + 3a + mb - 2
Rearranging, we get:
2a - mb = k - 2
Now we can use the fact that the system has infinitely many solutions to find values of k and m. Since the system has infinitely many solutions, the equation 2a - mb = k - 2 must be equivalent to one of the given equations. In other words, there must be values of k and m such that:
2a - mb = 2 - (3a + 2b)
Multiplying both sides by -1, we get:
3a + 2b - 2a + mb = -2
Simplifying, we get:
a + 2b + mb = -2
Now we have two equations:
2a - mb = k - 2
a + 2b + mb = -2
We can solve for k and m by eliminating one of the variables, say a or b, from the equations. Let's eliminate a by multiplying the second equation by 2 and subtracting it from the first equation:
2(2a - mb = k - 2) - (a + 2b + mb = -2)
Simplifying, we get:
3a - 5b = 2k - 2
Now we want this equation to be true for all values of a and b, which means the coefficients of a and b on the left-hand side must be equal to 0:
3a - 5b = 0
Equating the coefficients with the previous equation, we get:
2k - 2 = 0
Solving for k, we get:
k = 1
Now substituting k = 1 into the equation 2a - mb = k - 2, we get:
2a - mb = -1
Rearranging, we get:
mb - 2a = 1
We can solve for m by setting a = b = 1:
m - 2 = 1
Solving for m, we get:
m = 3
Therefore, the values of k and m that make the system have infinitely many solutions are k = 1 and m = 3.