If (a + b)^2 = 49......then either
a + b = 7 or a + b = -7
b = 7 - a or b = -7 - a
And if ab = 10, then either
a(7 - a) = 10 or a (-7 - a) = 10
7a - a^2 = 10 or -7a - a^2 = 10
Rearrange both as
a^2 - 7a + 10 = 0 or a^2 + 7a + 10 = 0
Factor
(a - 5) (a -2) = 0 or (a + 5) (a + 2) = 0
Setting each factor to 0, a takes on 4 values
a = -5, -2, 2 or 5
And using ab = 10, b = 10/a....so.......b = -10/5, 10/-2, 10/2 or 10/5 ....... and these values are b in terms of the value for a
