SSC Government Jobs Exams Numerical Ability Algebra

If a4 + a2 b2 + b4 = 8 and a2 + ab + b2 = 4, then the value of ab is-

Options
1) -1
2) 0
3) 2
4) 1

Read Solution (Total 1)

a4+a2b2+b4=8

so (a2+b2)2-a2b2=8

a2 + ab + b2 = 4 so

(a+b)2-ab=4

from 1st equation,

(a2+b2+ab)(a2+b2-2ab+ab)=8

4(4-2ab)=8

(4-2ab)=2

ab=1
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SSC Other Question

While selling, a businessman allows 40% discount on the marked price and there is a loss of 30%. If it is sold at the marked price, profit per cent will be If a, b, c, are three non-zero real numbers such that a + b + c = 0, and b2 ≠ ca, then the value of a2 + b2 + c2/ b2 –ca is-
Options
1) 3
2) 2
3) 0
4) 1