None of your options, not via complete the square nor quadratic the formula.
Solve for x over the real numbers:
x^2 + 8 x + 9 = 0
x = (-8 ± sqrt(8^2 - 4×9))/2 = (-8 ± sqrt(64 - 36))/2 = (-8 ± sqrt(28))/2:
x = (-8 + sqrt(28))/2 or x = (-8 - sqrt(28))/2
sqrt(28) = sqrt(4×7) = sqrt(2^2×7) = 2sqrt(7):
x = (2 sqrt(7) - 8)/2 or x = (-2 sqrt(7) - 8)/2
Factor 2 from -8 + 2 sqrt(7) giving 2 (sqrt(7) - 4):
x = 1/22 (sqrt(7) - 4) or x = (-2 sqrt(7) - 8)/2
(2 (sqrt(7) - 4))/2 = sqrt(7) - 4:
x = sqrt(7) - 4 or x = (-2 sqrt(7) - 8)/2
Factor 2 from -8 - 2 sqrt(7) giving 2 (-sqrt(7) - 4):
x = sqrt(7) - 4 or x = 1/22 (-sqrt(7) - 4)
(2 (-sqrt(7) - 4))/2 = -sqrt(7) - 4:
Answer: x = sqrt(7) - 4 or x = -sqrt(7) - 4_____________________________________________________
Solve for x:
x^2 + 8 x + 9 = 0
Subtract 9 from both sides:
x^2 + 8 x = -9
Add 16 to both sides:
x^2 + 8 x + 16 = 7
Write the left hand side as a square:
(x + 4)^2 = 7
Take the square root of both sides:
x + 4 = sqrt(7) or x + 4 = -sqrt(7)
Subtract 4 from both sides:
x = sqrt(7) - 4 or x + 4 = -sqrt(7)
Subtract 4 from both sides:
Answer: x = sqrt(7) - 4 or x = -4 - sqrt(7)
Answer:
The second one
Step-by-step explanation:
So the “certain number” will be S.
Since 2width + 2length, the first part would be 2 times 2 which is 4
The length is S - 3
We then have to multiply this by 2
So it is 2(S-3) which is 2S-6
So the answer is 4+2S-6 which is 2S-2
Answer: 3.5 h
Step-by-step explanation:
<u>1. Data:</u>
a) s = 740 miles / h
b) d = 2,567 miles
c) t = ?
<u>2. Equation:</u>
<u>3. Solution:</u>
- Solve the equation for t:
s = d / t ⇒ t = d / s
t = 2,567 miles / (740 miles/h) ≈ 3.47 h ≈ 3.5 h
11- 59.1. Got the Answer for #11, but for #12 you lowkey should just use any type of calculator for that shape
