Answer:
x = 11, -1
Step-by-step explanation:
First, let's identify what the quadratic formula is:
x = [-b ± √(b² - 4(a)(c))] / 2
Our equation is written in standard form:
ax² + bx + c = 0
x² - 10x - 11 = 0
Let's plug in what we know.
x = [-(-10) ± √((-10)² - 4(1)(-11))] / 2
Evaluate the exponent.
x = [-(-10) ± √(100 - 4(1)(-11))] / 2
Simplify the negatives.
x = [10 ± √(100 - 4(1)(-11))] / 2
Multiply.
x = [10 ± √(100 + 44)] / 2
Simplify the parentheses.
x = [10 ± √(144)] / 2
Simplify the radical (√)
x = [10 ± 12] / 2
Evaluate the ±.
x = [10 + 12] / 2
x = [22] / 2
x = 11
or
x = [10 - 12] / 2
x = [-2] / 2
x = -1
Your answers are x = 11, -1
Hope this helps!
Answer:
2z-6
Step-by-step explanation:
2(z-3)
2(z)-2(3)=2z-6
Step-by-step explanation:
4x2 - 25b2
We can solve it by the squares so
(2x - 5b) (2x + 5b)
2) x2 - 81
The same case is here so
(x - 9) (x + 9)
Answer:
f(x) = 2x^2 - 6x - 20.
Step-by-step explanation:
(-2, 0) and (5, 0) are 2 zeroes of the function so we can write the function as
f(x) = a(x + 2)(x - 5) where a is a constant.
Now as (4, -12) is a point on the graph:
-12 = a(4 + 2)(4 - 5)
-12 = a * 6 * -1
-6a = -12
a = 2.
So f(x) = 2(x + 2)(x - 5)
f(x) = 2x^2 - 6x - 20.
<span>So we need to find the lenght of side a of a right triangle if we know b=13 and c=21 and c is the hypotenuse and we need to round the number to the nearest hundreth. So we can do that with Pythagorean theorem which states that: a^2 + b^2 = c^2. Now we simply put b^2 to the right side and find a^2 as: a^2=c^2 - b^2. Lets plug in the numbers and we will get a= sqrt (21^2 - 12^2)=16.492422. When we round it to the nearest hundreth a= 16.49.</span>
