have a triangle 77º 50º and (7x-3)º how do i figure the third?

Question

have a triangle  77º  50º and (7x-3)º how do i figure the third?

campbell_st · Answer

angle sum of a triangle is 180 

so 

7x - 3 = 180 - 77 - 50

just solve for x

anonymous · Answer

iam sorry I dont know how to solve for x could you tell me how

anonymous · Answer

i do know the sum is 180 and I think the answer is 53 but how do i show this? thank you

whpalmer4 · Answer

$$7x-3=180-77-50$$$$7x-3 = 53$$Now add 3 to both sides, what do you get?
Divide both sides by 7, what do you get?

anonymous · Answer

so 
7x-3+3=53+3
sorry i dont understand how to add 3 to 7x-3

anonymous · Answer

7x - 3 + 3 = 7x

whpalmer4 · Answer

So where you're left is with $$7x - 3 + 3 = 53 + 3$$$$7x \cancel{-3 + 3} = 56$$$$7x = 56$$Divide both sides by 7\]$$\frac{7x}{7} = \frac{56}{7}$$$$\frac{\cancel{7}x}{\cancel{7}} = 8$$$$x=8$$Agreed?

Now plug $x=8$ into $7x-3$ to find the number of degrees of the mystery angle.  Check your work by adding the answer to 77 and 50 and verifying that you get 180.