Solve the system by substitution.
(x+y=6
y = x2 - 7x-9

Δabc is reflected across line l to form δ alblcl, and a¯¯¯al¯¯¯¯ intersects line l at point d. which equation is not necessarily true?

How much dextrose 70% must be mixed with dextrose 5% to prepare 1,000 ml of dextrose 20%?

Which value of m will create a system of parallel lines with no solution? y= mx - 6 8x - 4y = 12