Answer:
your question is wrong, it's not an expression but a quadratic equation. if so your answer will be x=8±2√7
Step-by-step explanation:
by using, completing the square method
x²-16x-4=0
x²-16x=4
x²-16x+(-16×0.5)²=4+(16×0.5)²
x²-16x-8²=4+8²
(x-8)²=68
x-8=√68
x-8=±2√7
so x=8±2√7
please next time write the correct question