Question

If x+2 is a factor of x2 +ax+8 then a =.....​

Answer 1

Hey Buddy

Here's The Answer

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Let,

p(x) = x² + ax + 8

Given : x + 2 is factor of p(x)

=> x + 2 = 0

=> x = -2

Then by factor theorem p( -2 ) = 0

=> p( x ) = x² + ax + 8

=> p( -2 ) = ( -2 )² - 2a + 8 = 0

=> 4 - 2a + 8 = 0

=> 12 - 2a = 0

=> 2a = 12

=> a = 6 ✓

Hope It Helps.