Step-by-step explanation:
8x-3x = 18-3(like terms)
or,5x = 15
or,x=15/5
or,x=3
For problems like this you can move the y's on the bottem up top by fliping the sign of the exponent (in this case 7 to -7) and MULTIPLYING it with EVERYTHING on top, then because of properties of multplication you can add the exponents to combine them into one term (in this case add 3 and -7 to get -4)

If any of this does not make sense let me know and ill try to clarify better
Answer:
n^2 - n - 12 = (n+3)(n-4)
Step-by-step explanation:
3 times - 4 = -12 ( two numbers when multiplied = -12, when added=-1)
3 + -4 = -1
The rule to find the term is: y=225-4x
you want to know the 82nd term which occurs when x=82 therefore
y = 225-(4 x 82) = -103
82nd term = -103
X > 90 idk if thats what u mean or not