solve 9/(2x^2+7x+5) - 3/(2x^2+9z+10) TO add or subtract fractions the denominator needs to be the same (bottom). They are not in this case. multiply the top by the other fractions bottom.
9(2x^2 + 9z + 10) - 3(2x^2 + 7x + 5)/(2x^2 + 7x + 5)(2x^2 + 9z + 10) this is the fraction with a common denominator. solve it.
18x^2 + 18z + 90 - 6x^2 + 14x + 15/(2x^2 + 7x + 5)(2x^2 + 9z + 10)
12x^2 + 18z + 14x + 105/(2x^2 + 7x + 5)(2x^2 + 9z + 10)