+118608 You might find it easier if you swap the z for an x and the swap it back at the end
\((4-z)(z+7) ≥ 2\\ (4-x)(x+7) ≥ 2\\ -x^2 -3x +28 \ge 2\\ -x^2 -3x +26 \ge 0\\ x^2+3x -26 \le 0\\ \)
\(y=x^2+3x-26\\ \text{Is a concave up parabola}\)
So it will be less than 0 between the roots. Draw it to see what i mean
Use the quadratic formula to find the roots
etc
