Answer:
4 parameters are necessary to specify all solutions and correspond to the number of free variables of the system.
Step-by-step explanation:
Remember that the number of free variables of a system is equal to m-rank(A) where m is the number of unknowns variables and A is the matrix of the system.
Since the system is consistent and the rank of the matrix is 3 then echelon form of the augmented matrix has two rows of zeros.
Then m-rank(A)=7-3=4.
We have to divide 9/10 by 3/12.
if we divide by a fraction, we can instead multiply by it's inverse:

so now we count:

so we can cut exactly 3 pieces!
2+4a=-10
First, subtract 2 from both sides.
4a=-12
Then divide 4 from both sides.
a=-3
hope it helps!
Answer:
Is there a picture to go with it?
Step-by-step explanation: