book Maths Puzzle Numerical Ability

I have looked in so many places to find a solution or method for this, and I have not succeeded. I would appreciate some help!

f(x) = 0

f(x) = x^2 + 2x - 1

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book Other Question

I need help on solwing this linear equation by substitution..
3x-y=7
y=x+3
The lines satsifying the equations x + dy=3 and 3y +ax=2 are perpendicular to each other find a