Answer:
392
Step-by-step explanation:
7(8) + 3(8)(14)
56 + 336
=392
*Brackets mean to multiply.
Answer:
900
Step-by-step explanation:
Sum of interior angle for a polygon = (n-2)180
7 sides
=(7-2)180
=5*180
=900
Let's solve this by using the quadratic formula:

Note that we only use the coefficients so a=12, b=-14, and c=-6.
Plug values in the quadratic equation:

And so by evaluating those values we obtain:

Now we have two answers which are our factors one where we add another where we subtract and so:
First factor:

Second Factor:

And so your factors are

meaning that those are your roots/x-intercepts.
Do 12-5 then 6.4 then 2.2 then whatever answer you get for 12-5 multiply it by the answer you get for 6.4 then subtract whatever answer you get for 2.2 hope this helps!
Rearranging the first equation:-
3x - 4y = -7
9x + 4y = 139
12x = 132
x = 132/12 = 11
Substituting fro x in the second equation:-
9(11) + 4y = 139
4y = 139 - 99 = 40
y = 40/4 = 10
Answer x = 4 , y = 10.