Question

Which value of x solves the equation cos x° = sin (20° + x°), where
0 < x < 90?

Answer 1

Answer choices
A.30°
B.35°
C.40°
D.45°
E.55°

Answer 2

think of right triangle

from this you can say
cos x = sin (90 -x)

--> sin(90-x) = sin(20+x)

--> 90 -x = 20+x

solve for x

Answer 3

I'm confused, I think I missed a step because i did the 90-x=20+x part and all of them equal up to 110.
Where did i go wrong?

Answer 4

WAIT is it 35?

Answer 5

you did your algebra wrong then
add x to both sides

--> 90 = 20 + 2x

subtract 20 from both sides

--> 70 = 2x

Answer 6

haha yes correct :)

Answer 7

Thank you sooo much!