Solve 5x^2 - 9x + 4 = 0 using the quadratic formula

The quadratic formula is (-b±sqrt(b^2-4ac))/2a where a is the coefficient of the x^2 term, b is the coefficient of the x term and c is the number. So, in this case a=5, b=-9 and c=4. Substitute this into the formula to get (9±sqrt(9^2-4x5x4))/2x5. This simplifies to (9+1)/10 and (9-1)/10 which gives x= 1 or 0.8.