Answer:
6 is the answer
Explanation:
Equation A:
y=6x-b
Equation B:
-3x+1/2y= -3
If the system of equation has infinite number of solutions then Equation A is equal to Equation B.
We will take equation B and move all the values to the R.H.S and isolate variable y
-3x+1/2y = -3
1/2y= -3 +3x
Multiply both sides by 2
2 * 1/2y = 2(-3+3x)
y = -6+6x
y = 6x-6 ------- Equation B(I)
Now equate Equation A and Equation B(I)
6x-b = 6x-6
Subtract 6x from both sides.
6x-6x-b = 6x-6x - 6
-b = -6
Negative sign will be cancelled out by each other.
b = 6