Find a if x-5 is a factor of x^ -4x^ + ax +60
Answers
Answered by
0
a = - 17
Explanation:
Let, f(x) = x³ - 4x² + ax + 60
Since (x - 5) is a factor of f(x), then x = 5 is a solution of f(x) = 0
⇒ f(5) = 0
⇒ 5³ - 4 × 5² + a × 5 + 60 = 0
⇒ 125 - 100 + 5a + 60 = 0
⇒ 5a + 85 = 0
⇒ 5a = - 85
⇒ a = - 85 / 5
⇒ a = - 17
Answered by
1
Answer:
Correct option is
A
15
Since, (x -2) is one factor of x
2
+ax−6=0
⇒2
2
+a(2)−6=0
⇒2a=2⇒a=1 ...(i)
Again as (x -2) is factor of x
2
−9x+b=0
⇒2
2
−9(2)+b=0
⇒b=14 ...(ii)
Now, a+b=1+14=15
Hence, Option A is correct.
Similar questions