The second one. All the other ones have degree 6.
28.50x + 110.99(14-x)=811.45
distribute
28.50 x + 1553.86-110.99x =811.45
combine like terms
-82.49x+1553.86=811.45
subtract 1553.86 from each side
-82.49x =-742.41
divide by -82.49
x=9
He bought 9 of the 28.50 features and 5 of the 110.99 features
ANSWER: a=12 b=15
Explanation: (look at work below)
4a + 1b = 63 (eq1)
5a + 3b = 105 (eq2)
-12a + -3b = -189 (subt. eq1 from eq2)
————————-
-7a = -84
a = 12
4(12) + 1b = 63 (plug in the a value)
48 + 1b = 63
b = 15
Y - 3 = 5(x - 4)
y - 3 = 5x - 20
y = 5x - 20 + 3 = 5x - 17
=> slope = 5
For perpendicular line, m2 = -1/m1 = -1/5