Question

x^2+ax-8=0 ; x=4 than a=?​

Answer 1

Step-by-step explanation:

for x=4

x^2+ax-8=0

=>(4)^2+a×4-8=0

=>16+4a-8=0

=>4a+8=0

=>4a= -8

=>a= -8/4

=>a= -2

Answer 2

Answer:

a=−2

Step-by-step explanation:

Let p(x)=x^2 +ax−8=0;  

where 4 is one of the roots.

⟹p(4)=0

⟹(4)^2 +a(4)−8=0

⟹16+4a−8=0

⟹4a=−8

∴ a=−2