Answer:
c=4
Step-by-step explanation:
If polynomial p(x) is divisible by (x-3), then x=3 is zero of p(x).
p(x) =-x^3+cx^2-4x+3
0=p(3)=-3^3 +c*3^2 - 4*3+3
0=-27+9c-12+3
0=-27-9+9c
0=-36+9c
36=9c
c=36/9
c=4
Regroup:
(x^4+2x^2-8)-(x^3+4x)=0
Factor: (x^2-2)(x^2+4)-x(x^2+4)=0
both terms have (x^2+4), so (x^2+4)(X^2-x-2)=0
factor again: (x^2+4)(x+1)(x-2)=0
x=1, x=2, x=2i, or x=-2i
Answer:
5 and 35
Step-by-step explanation:
Answer:
120 = 15x + 45 5 hours of lessons
Step-by-step explanation:
120 is total money so that goes on one side.
45 is a one-time cost so it is on its own.
15 per hour is another cost but this one depends on a variable so it has an x.
X represents the number of hours.
You put this together to from the equation: 120 = 15x + 45.
Subtract 45 from both sides: 75 = 15x
Divide 15 from both sides: 5 = x.
X = hours so 5 hours