Answer:
![x=2+\frac{1}{2}\sqrt[]{21}](https://tex.z-dn.net/?f=x%3D2%2B%5Cfrac%7B1%7D%7B2%7D%5Csqrt%5B%5D%7B21%7D)
or

Step-by-step explanation:

Add 21 on both sides.


a=4
b=-16
c=-5
![x=\frac{-b\frac{+}{}\sqrt[]{b^2-4ac} }{2a}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-b%5Cfrac%7B%2B%7D%7B%7D%5Csqrt%5B%5D%7Bb%5E2-4ac%7D%20%20%7D%7B2a%7D)
![x=\frac{-(-16)\frac{+}{}\sqrt[]{(-16)^2-4(4)(-5)} }{2(4)}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-%28-16%29%5Cfrac%7B%2B%7D%7B%7D%5Csqrt%5B%5D%7B%28-16%29%5E2-4%284%29%28-5%29%7D%20%20%7D%7B2%284%29%7D)
![x=\frac{16\frac{+}{}\sqrt[]{256+80} }{8}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B16%5Cfrac%7B%2B%7D%7B%7D%5Csqrt%5B%5D%7B256%2B80%7D%20%20%7D%7B8%7D)
![x=\frac{16\frac{+}{}\sqrt[]{336} }{8}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B16%5Cfrac%7B%2B%7D%7B%7D%5Csqrt%5B%5D%7B336%7D%20%20%7D%7B8%7D)
![x=\frac{16\frac{+}{}\sqrt[]{2^2*2^2*21} }{8}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B16%5Cfrac%7B%2B%7D%7B%7D%5Csqrt%5B%5D%7B2%5E2%2A2%5E2%2A21%7D%20%20%7D%7B8%7D)
![x=\frac{16\frac{+}{}2*2\sqrt[]{21} }{8}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B16%5Cfrac%7B%2B%7D%7B%7D2%2A2%5Csqrt%5B%5D%7B21%7D%20%20%7D%7B8%7D)
![x=\frac{16\frac{+}{}4\sqrt[]{21} }{8}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B16%5Cfrac%7B%2B%7D%7B%7D4%5Csqrt%5B%5D%7B21%7D%20%20%7D%7B8%7D)
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![x=\frac{16}{8}+\frac{4\sqrt[]{21}}{8}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B16%7D%7B8%7D%2B%5Cfrac%7B4%5Csqrt%5B%5D%7B21%7D%7D%7B8%7D)
![x=2+\frac{1}{2}\sqrt[]{21}](https://tex.z-dn.net/?f=x%3D2%2B%5Cfrac%7B1%7D%7B2%7D%5Csqrt%5B%5D%7B21%7D)
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![x=\frac{16}{8}-\frac{4\sqrt[]{21}}{8}\\x=2-\frac{1}{2}\sqrt{{21}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B16%7D%7B8%7D-%5Cfrac%7B4%5Csqrt%5B%5D%7B21%7D%7D%7B8%7D%5C%5Cx%3D2-%5Cfrac%7B1%7D%7B2%7D%5Csqrt%7B%7B21%7D)
Answer:
1000
Step-by-step explanation:
Answer:
∠D B C = 41°
Step-by-step explanation:
<u><em>Step(i)</em></u>:-
Given ∠ABC = 90°
In diagram ∠D B C + ∠A B D = 90°
6 x+5 + 8 x +1 = 90
14 x + 6 = 90
14 x = 90 -6
14 x = 84
<em> x = 6</em>
<u><em>Step(ii):-</em></u>
∠D B C = 6 x + 5 = 6 (6) +5 = 36 +5 = 41
<em>∠D B C = 41°</em>
<em> ∠A B D = 8(6) +1 = 49°</em>
<em>∠D B C + ∠A B D = 41° + 49° = 90°</em>