You need to use division.
Answer:
option A and B

and

Step-by-step explanation:
we have

The formula to solve a quadratic equation of the form
is equal to

in this problem we have

so

substitute in the formula


so

and

Answer:
yes ur right
Step-by-step explanation:
So we are given a system:

Substitute x = 2 we get the system:

Multiply the first equation by -5 and the second by 2 we get the system:

Adding the two equations we get :

We find the value of y by using any of the other equations like this:

Final solution:
0.3*42 this gives you a 30% discount
3/10*42 this gives you a 30% discount
0.03*42 this gives you a 3% discount
3 *4.2 This is not a discount