Solutions to 2 variables equations

-4x+7=2y-3

a) only (2,1)
b)only (5,-5)
c) both
d) neither

At the olympic games, many events have several rounds of competition. one of these events is the men's 100-meter backstroke. the upper dot plot shows the times (in seconds) of the top 8 finishers in the final round of the 2012 olympics. the lower dot plot shows the times of the same 8 swimmers, but in the semifinal round. which pieces of information can be gathered from these dot plots? (remember that lower swim times are faster.) choose all answers that apply: a: the swimmers had faster times on average in the final round. b: the times in the final round vary noticeably more than the times in the semifinal round. c: none of the above.

Which expression shows the sum of the polynomials with like terms grouped together

Bring the fraction a/a-4 to a denominator of 16-a^2