Hi There.
First you'll put the "like terms" together..
4x^2-5-16x^2+10+8x
=(4x^2 -16x^2)+8x+(10-5)
to get
-12x^2+8x+5
For Solving,
Using " x = [ -b ± √(b2-4ac) ] / 2a " as the formula to find 'x' , you'll have:
x = [ -b ± √(b2-4ac) ] / 2a
x = [ -8 ± √[8^2 - (4 x -12 x 8)] / (2 x -12) ]
the formula gives you two answers:
x1 = -25.43559
x2= 9.43559
Therefore, taking the positive value,
x = 9.43559 .
Good Luck..!
