scientific notation should have one positive in front of the decimal point, then any number (>=1) of positions after the decimal point, followed by the multiplication with the property power of 10.
the only number not following that rule is b (2 positions in front of the decimal point).
4x - 2y = 6
2x - y = 3
are the same line, as we can multiply the second equation by 2 and get exactly equation 1.
so, both lines have the same slope and the same y-intercept. therefore, they have infinitely many solutions.
