3x^3y ( 6xy + 7x^2 − 2y ) is the factored form. Factor 3x^3y out of the equation.
Answer:
C. 
Step-by-step explanation:
I think the equation meant 
?
Anyways, to factor these kinds of quadratic, keep into consideration:
ONLY if:
Start off by finding factors of c, which in this case, -18:
±(1, 2, 3, 6, 9, 18)
If one of the numbers is negative then the other number must be positive.
Find which two factors will sum up to b, which in this case, is 3.
The only two factors that work are 6 and -3.
Replace them into the factored form:
In this diagram we see that 80 and 3x+4y are both vertical angles and vertical angles are congruent or always equal so we can set those two equations equal to each other then we can see that a line splits two angles making them supplementary (they equal 180 degrees) So we can have another equation, the two equations are:
3x+4y=80 and 3x+4y+7x-8y=180 (add like terms to simplify and get 10x-4y=180
Then use elimination to get rid of the y variables
10x-4y=180 (plus)
+3x+4y=80 (the negative 4 and positive 4 cancels each other out so you are left with:)
13x=160 (divide by x)
x=12.30769 which can be rounded to x=12.31
Then we have to plug in x into the first equation:
3(12.31) + 4y = 80
36.93 + 4y = 80 (subtract 36.93 from 80)
4y = 43.07 (divide)
y=10.7675 or rounded to 10.77
so x=12.31 and y=10.77
