9x squared plus 4x -5 equals 0?

Answer 1

X is equal to -1, her's my working out:

1. add 5 to both sides= 9x2+4x=5
2. -4x from both sides= 9x2=5-4x
3. square root both sides, then re-square (this may be incorrect) to get 9x=5-4x
4. add 4x to both sides= 9x=4x=5
5. use trial and error to guess x =-1

Substitute -1 into your original equation (be careful with minus signs etc) and you'll find -1 is correct.