Question

solve the whole paper
and don't give non sense answers​

Answer 1

I) a+1/a=7

=(a+1/a) ^2=(7)^2

=,a^2+ 2+1/a^2=49

a^2+1/a^2=47

(False)

ii) (3a-4b+2)×(5a+6) [a=1, b=-2]

={3×1-4×(-2) +2}×{5×1+6}

=(3+8+2) ×(5+6)

=13×11

=143

III) x^2-y^2 [x+y=9, xy=14]

=(x+y) ^2-4xy

=9^2-4×14

=81-56

=25

iv) 9x^2+4y^2 [3x+2y=12, xy=6]

=(3x) ^2+(4y) ^2

=(3x+4y) ^2-2xy

=(12) ^2-2×6

=144-12

=132

v) 9x^2+25y^2 [3x-5y=10,xy=5]

=(3x)^2+(5y)^2

=(3x-5y)^2+2xy

(10)^2+2×5

=100+10

=110