X = 77.789
y = 23...............................

Let
, so that differentiating both sides wrt
gives

If
and
, the above reduces to

This is the slope of the tangent line, which has equation

Answer:
B 100%
Step-by-step explanation:
Answer:
x + y = ±15
Step-by-step explanation:
Step 1: Write out systems of equations
x - y = 1
xy = 56
Step 2: Rearrange 1st equation
x = y + 1
Step 3: Substitution
(y + 1)y = 56
Step 4: Distribute
y² + y = 56
Step 5: Solve for <em>y</em>
y² + y - 56 = 0
(y - 7)(y + 8) = 0
y = -8, 7
Step 6: Plug in <em>y </em>to find <em>x</em>
x - 7 = 1
x = 8
x - (-8) = 1
x + 8 = 1
x = -7
Step 7: Find answer
x + y = ?
8 + 7 = 15
-7 + -8 = -15
So both 15 and -15 could be the answer.
The equation has no solution