Answer:
c =
km
Step-by-step explanation:
Here's the required formula to find the missing side of triangle by pythagoras theorem :

a = 20 km
b = 21 km
c = ?
Substituting all the given values in the formula to find the third side of triangle :

Hence, the length of missing side of triangle is 29 km.

Answer:
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Step-by-step explanation:
Answer:
x = -1.14 or -13.14
Explanations:
The given equation is:

Find the half of 12, and add the square to both sides of the equation.
That is add 6² to both sides


Find the square root of both sides:
![\begin{gathered} \sqrt[]{(x+6)^2_{}}=\pm\sqrt[]{51} \\ \text{x + 6 = }\pm\sqrt[]{51} \\ x\text{ = -6 }\pm\sqrt[]{51} \\ \text{x = }-6\pm7.14 \\ x\text{ = -6+7.14 = }1.14 \\ x\text{ = -6 - 7.14} \\ \text{x = -13.14} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20%5Csqrt%5B%5D%7B%28x%2B6%29%5E2_%7B%7D%7D%3D%5Cpm%5Csqrt%5B%5D%7B51%7D%20%5C%5C%20%5Ctext%7Bx%20%20%2B%20%206%20%20%3D%20%7D%5Cpm%5Csqrt%5B%5D%7B51%7D%20%5C%5C%20x%5Ctext%7B%20%20%3D%20%20-6%20%20%7D%5Cpm%5Csqrt%5B%5D%7B51%7D%20%5C%5C%20%5Ctext%7Bx%20%20%3D%20%7D-6%5Cpm7.14%20%5C%5C%20x%5Ctext%7B%20%20%3D%20-6%2B7.14%20%20%3D%20%7D1.14%20%5C%5C%20x%5Ctext%7B%20%3D%20-6%20-%207.14%7D%20%5C%5C%20%5Ctext%7Bx%20%3D%20-13.14%7D%20%5Cend%7Bgathered%7D)
x = -1.14 or -13.14
We have that
f(x) = –4x²<span> + 24x + 13
</span>
we know that
The vertex form for a parabola that opens up or down is:
f(x) = a(x - h)^2 + k
in the given equation, <span>a=-4</span><span>, therefore we add zero to the original equation in the form of </span><span>4h</span>²<span>−4h</span>²
f(x) = –4x² + 24x + 4h²−4h² +13
<span>Factor 4 out of the first 3 terms and group them
</span>f(x) = –4*(x² -6x +h²) +4h² +13
<span>We can find the value of h by setting the middle term equal to -2hx
</span>−2hx=−6x
<span>h=3</span><span> and </span><span>4h</span>²<span>=<span>36
</span></span>f(x) = –4*(x² -6x +9) +36 +13
we know that the term (x² -6x +9) is equals to------> (x-3)²
so
f(x) = –4*(x-3)² +49
the answer isf(x) = –4*(x-3)² +49
Answer liner
Step-by-step explanation: