can someone please help me with this and the first to answer will get marked as brainiest also i need the work to be shown cause i know the answer but just not the work cause i’m confused pls help

x = 3

Step-by-step explanation:

a triangle has 180 degrees in all

a square for an angle is 90 degrees

we can add them all together and get 180

90 + 45 + 8x + 21 = 180

combine like terms

156 + 8x = 180

subtract 156 to each side

8x = 24

then find x

x = 3

x=3

Step-by-step explanation:

So the sum of angles of triangle is always 180 degrees.

We already have 45 and 90 but 8x+21 is unknown.

We can solve this by making an equation which is

45 + 90 + (8x+21) = 180.

If we solve this it will be

8x+21+135=180

8x+156 (-156) =180 (-156)

8x (/8) = 24 (/8)

x=3

sorry man i accidentally pressed yes my bad

step-by-step explanation:

b and c

step-by-step explanation: