Solve:

Log5x=log(2x+9)

Using the  

law of logarithms

∣

∣

∣

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

a

a

log

x

=

log

y

⇒

x

=

y

a

a

∣

∣

−−−−−−−−−−−−−−−−−−−−−−−  

⇒

5

x

=

2

x

+

9

⇒

3

x

=

9

⇒

x

=

3

Step-by-step explanation:

c. side angle side. u shares the same sides

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.