15 increased by a number x: 15 + x
a number x more than −14: x > -14
t<span>he difference of 7 and a number x: </span>7/x
The number of solutions of a quadratic equation
ax^2+bx+c=0
Depends on its discriminant
/Delta=b^2-4ac
If /Delta>0 there are two distinct solutions
If /Delta=0 there are two coincident solutions
If /Delta<0 there are no solutions.
We know that there are two real solutions (I assume you mean distinct solutions), so we know that the discriminant is positive:
The number of solutions of a quadratic equation
Depends on its discriminant
If there are two distinct solutions
If there are two coincident solutions
If there are no solutions.
We know that there are two real solutions (I assume you mean distinct solutions), so we know that the discriminant is positive:
b^2-4ac=9+28t>0\iff t>-\dfrac[9][28]
