Answer:
D = -47
Step-by-step explanation:
-9x²+5x-2 = 0 (a = -9, b = 5, c = -2)
D = b² - 4ac
= 5² - (4*-9* -2) =
25 - (72) = -47
Answer:
90
Step-by-step explanation:
Answer:
<em>Sam is 24 years old and his mother is 48 years old.</em>
Step-by-step explanation:
<u>Equations</u>
Let's call
x = Sam's current age
Since Sam's mother is twice as old as Sam:
2x = Sam's mother current age
x + 12 = Sam's age in 12 years
2x - 12 = Sam's mother age 12 years ago
These two last expressions are equal:
x + 12 = 2x - 12
Subtracting x and adding 12:
x = 24
2x = 48
Sam is 24 years old and his mother is 48 years old.