Find the number of solutions of the equation 5t2 + 3t − 7 = 0 by using the discriminant.

Below in BOLD.

Step-by-step explanation:

1.  The discriminant D = b^2 - 4ac

= 3^2 - 4*5*(-7)

= 9 + 140

= 149.

Positive value so it has 2 real solutions.

2. D = (-12)^2 - 4 * 9 * 4

= 144 - 144

= 0.

So it has one real solution.

3.  D =  2^2 - 4*1*3

= -8.

It is negative so there are No real solutions.

4.  D = 4^2 - 4*2*10 = 16 - 80 = -64.

No solutions.

5. D = (-12)^2 - 4*3*(12)

= 144 - 144 = 0

So its the second choice.

$450 is the answer.

step-by-step explanation:

30% of 450 = 135

450-135=315