You need this key result: in any polygon, the sum of the interior angles is
where 
is the number of sides of the polygon.
Your polygon has seven sides, and the measures of all angles are given. So, we can write
Again, we've simply written that the sum of all interior angles is the number of sides, minus two, times 180.
We can simplify both sides: we sum like terms on the left hand side, and we easily compute the right hand side:
and we can solve this equation for 
by dividing both sides by 30:
Finally, the required angles is 
Step-by-step explanation:
9x-3=42
9x=42+3
9x=45
9x/9=45/9
x=5
Answer:
C - 10
Step-by-step explanation:
n is the number of the term
an = -2n+8
a9 = -2*9 +8
a9 = -18+8
a9 = -10
The 9th term is -10
Answer: x = -1
Step-by-step explanation:
(4x + 4) + 4 = 4 subtract 4 from each side
(4x + 4) = 0 subtract 4 from each side again
4x = -4 divide each side by 4
x = -4/4
x = -1
Answer: Interest rate is: $800
Step-by-step explanation: add 400 + 40 and equal that to 800 basically on how i did it was i used my mathematics calculator and it had 800 on it so yeah hope this help
