# Determinant question

azzarooni88

Q54.

## Homework Equations

Cofactor expansion (along 1st column)

## The Attempt at a Solution

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Mentor

## Homework Statement

View attachment 225748

## Homework Equations

Cofactor expansion (along 1st column)

## The Attempt at a Solution

View attachment 225746
What happened to your equation. You're starting with the determinant equalling 0. You lost one side of your equation.

azzarooni88
What happened to your equation. You're starting with the determinant equalling 0. You lost one side of your equation.
solving the determinant equal to 0

Mentor
solving the determinant equal to 0
If you're solving an equation, you have to actually have an equation.
In your first line, you start off with "= ..." followed by a bunch of expressions. You seem to have lost one side of your equation.

azzarooni88
If you're solving an equation, you have to actually have an equation.
In your first line, you start off with "= ..." followed by a bunch of expressions. You seem to have lost one side of your equation.
I think my working is logical. I start off with 0=... and just don't continue writing 0 on the LHS as I solve for the RHS. Ultimately I get 0=x2 - x(b+a) +ab