I have two unknown numbers x and y, and the sum of x and y(x+y) is 78 and the product is (x*y) is 896
Eq1: X + Y + 78.
Eq2: XY = 896.
X + Y = 78,
X = 78 - Y.
Substitute 78 - y for X in Eq2:
(78 - y)y = 896,
-Y^2 + 78Y - 896 = 0,
Multiply both sides by -1:
y^2 -78y + 896,
Use Quad. Formula to find y:
Y = 64, and 14.
Substitute 64 for y in Eq1:
X + 64 = 78,
X = 14.
Substitute 14 for y in Eq1:
X + 14 = 78,
X = 78 - 14 = 64.
Solution set: (14 , 64), (64, 14).