Question

if -1 is a zero of a polynomial f(x)=x2-7x-8 calculate the other zero...


Please give the answer ...​

Answer 1

FINAL ANSWER:-

the other zero is 8

GIVEN:-

one zero of polynomial x²-7x-8 is $\alpha =-1$

TO FIND:-

the other zero polynomial P(x)=x²-7x-8

THINGS TO KNOW:-

polynomial structure ⇒ ax²+bx+c

sum of zeroes =  →

product of zeroes = →

SOLUTION:-

if one of zero of x²-7x-8 is -1 [means alpha ($\alpha$)=-1]

so , let the another zero be $\beta$

in P(x)=x²-7x-8

a=1

b=-7

c=-8

∴$\alpha +\beta =\frac{-b\:\:(coefficient\:of\:x)}{a\:\:(coefficient\:of\:x^{2})}$

$-1+\beta =\frac{-(-7)}{1}$  ⇒  $-1+\beta =\frac{7}{1}$

$\beta =7+1$

$\beta =8$

the other zero is 8

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let's cross-check the answer

$product \:of\:zeroes=\frac{c}{a}\\\alpha \beta =\frac{c}{a}\\-1b=\frac{-8}{1}\\-\beta =-8\\\beta =8$

hence as we are getting $\beta$ as 8 implies we have done it find it correctly

Answer 2

maihuunknown ne sahi answer diya hai use brainlist bana do