Answer:
x = -1 ± √109
Step-by-step explanation:
2x • 3x + (2 • 3)x + 6x = 648
According to PEMDAS (parentheses/exponents | multiplication/division | addition/subtraction), we should solve the parentheses first.
(2 • 3) = 6
Now we have:
2x • 3x + (6)x + 6x = 648
Now let's multiply.
2x • 3x = 6x²
6 • x = 6x
Now we have.
6x² + 6x + 6x = 648
Combine like terms.
6x² + 12x = 648
Let's factor out a 6.
6(x² + 2x) = 648
Divide both sides by 6.
x² + 2x = 108
Let's use completing the square.
Our equation is in a² + bx = c form.
Divide b by 2.
2/2 = 1
Then square it.
1² = 1
Add 1 to both sides.
x² + 2x + 1 = 108 + 1
Simplify.
x² + 2x + 1 = 109
Now we want to factor the left side. A shortcut is just to use b/2.
(x + 1)² = 109
Take the square root of both sides.
x + 1 = ±√109
The square root is as simplified as possible.
Subtract 1 from both sides.
x = -1 ± √109
Hope this helps!
Answer:
c
Step-by-step explanation:
Answer:
1/4
Step-by-step explanation:
Mrs. Lincoln has 15 girls and 10 boys in her homeroom. She randomly selects two students. The total number of students is 25.
The probability of choosing one girl is:
15 / 25 = 3 / 5
Now, 24 students are left.
The probability of choosing one boy is:
10 / 24 = 5 / 12
Therefore, the probability of choosing one girl and one boy is:
3 / 5 * 5 / 12
= 3 / 12
= 1/4
It's a isosceles right angled triangle
