1) x + y = 5 2) 4x - 2y = 20
3) 4x - 3y =12
4) 6x - y= 18
pls help me for 50 brainlist!!

Jonathan can throw a baseball 10 1/3 yards. his brother joey can throw a baseball 13 1/2 yards. how much father can joey throw the ball?

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18

Do one of the following, as appropriate: (a) find the critical value z subscript alpha divided by 2 , (b) find the critical value t subscript alpha divided by 2 . 99%; nequals 17; sigma is unknown; population appears to be normally distributed.