Use the substitution method to solve the system of equations. Choose the
correct ordered pair.
x + y = 3
y= 9
A. (-6,9)
B. (12,9)
C. (-12,9)
D. (6,9)

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. 4x^2 + 20x + 25 = 0

Write the expression as a single natural logarithm. 2 in a - 4 in y

What does the sign of the slope tell you about a line?