Function maxResidual

test/compute-engine/solve.test.ts:776–783

(mj: any)

      .sort((a: number, b: number) => a - b);

  test('should solve |x| = 2 (both roots)', () => {
    // Regression: the |ax+b|+c root rule had a sign error and a malformed
    // second branch, so this returned only [2] (or garbage).
    expect(roots('|x| = 2')).toEqual([-2, 2]);
  });

  test('should solve |x - 1| = 2 (unit coefficient)', () => {
    expect(roots('|x - 1| = 2')).toEqual([-1, 3]);
  });

  test('should solve |2x - 1| = 3', () => {