3 years ago

Which expressions are equivalent to

Mathematics

1 answer:

Tamiku [17]3 years ago

3 0

I don’t understand eaither sorry

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Someone please help me!

bija089 [108]

Answer:

A = 58

B =:25

Step-by-step explanation:

C = A + B

83 = 9x + 4 + 4x + 1

83 = 13x + 5

13x = 78

x = 78/13

x = 6

A = 9x + 4 = 9 x 6 + 4 = 58

B = 4x + 1 = 4 x 6 + 1 = 25

7 0

2 years ago

Using the Law of Cosines, in triangle DEF, if e=18yd, d=10yd, f=22yd, find measurement of angle D

Ivahew [28]

Check the picture below.

$\bf \textit{Law of Cosines}\\ \quad \\
c^2 = {{ a}}^2+{{ b}}^2-(2{{ a}}{{ b}})cos(C)\implies 
c = \sqrt{{{ a}}^2+{{ b}}^2-(2{{ a}}{{ b}})cos(C)}
\\\\\\
\cfrac{{{ a}}^2+{{ b}}^2-c^2}{2{{ a}}{{ b}}}=cos(C)\implies cos^{-1}\left(\cfrac{{{ a}}^2+{{ b}}^2-c^2}{2{{ a}}{{ b}}}\right)=\measuredangle C\\\\
-------------------------------\\\\
\begin{cases}
d=10\\
e=18\\
f=22
\end{cases}\implies cos^{-1}\left(\cfrac{{{ 18}}^2+{{ 22}}^2-10^2}{2(18)(22)}\right)=\measuredangle D$

$\bf \implies cos^{-1}\left(0.893\overline{93}\right)=\measuredangle D\implies 26.63^o\approx \measuredangle D$