Determine the numerical value of y = (a+1) (b+1), Knowing that ab = - 6 and a+b=1

Question

Zayden

Mathematics

21 February, 12:46

Determine the numerical value of y = (a+1) (b+1), Knowing that ab = - 6 and a+b=1

+2

Answers (1)

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Emely Blair · Answer 1

Y = (a+1) (b+1)

ab=-6

a+b=1

a=1-b

(1-b) b=-6

-b^2+b+6=0

Δ=25, so b=3 or b=-2

Case 1: b=3, a+b=1, a+3=1, a=-2

y = (-2+1) (3+1) = - 4

Case 2: b=-2, a+b=1, a-2=1, a=3

y = (3+1) (-2+1) = - 4

So the value of y = (a+1) (b+1) = - 4