How do I solve this and check all the solutions?

x = 2

Step-by-step explanation:

(Square both sides)

20 - 8x = x^2

(Solve 20 - 8x = x^2)

x = 2 , x = 10

x = 10 is false, so the answer is x = 2.

x=2

Step-by-step explanation:

√20-8x=x

2√5-2x=x (by simplfing redical expression)

4(5-2x)=x^2 (square both side)

20-8x=x^2

20-8x-x^2=0

-x^2-8x+20=0

x^2+8x-20=0

x=2

Note:There is a another answer x=-10 But it's wouldn't fit out with this equation

282 6/7 cm^2

step-by-step explanation: