algebra
posted by tara on .
Use the method of substitution to solve the system.
xy=1
4xy+3=0

xy = 1,
4x  y + 3 = 0.
Solve 1st Eq for x:
X = 1/y,
Substitute 1/y for x in EQ2:
4/y  y + 3 = 0,
Multiply both sides by y:
4 + y^2  3y = 0,
y^2  3y  4 = 0,
Factor the trinomial:
(y + 1) (y  4) = 0,
y + 1 = 0,
y = 1.
y  4 = 0,
y = 4.
Substitute 1 for y in Eq1:
x*1 = 1,
x = 1.
Substitute 4 for y in Eq1:
x * 4 = 1,
x = 1/4.
Solution set: (1 , 1) , (1/4 , 4).