Question

Mai and Jada are solving the equation 2.02 – 7,0 = 15 using the quadratic formula but found different solutions. Jada wrote: -(-7)+7-72 – 4(2)(-15) 2(2) 7+/-49- (-120) X = Mai wrote: -7 +72 - 4(2)(-15) 2(2) -7 +49-(-120) 4 -7 + 169 4 -7 + 13 4 3 = -5 2 * 7 + 71 x 4 х or X = If this equation is written in standard form, ax? - bx+c= 0, what is the value of c? Use + or - as needed when filling in your answers.

Answer 1

When using the quadratic formula, we always need to write the quadratic equation in standard form to see for the values of a, b and c. If we rewrite the quadratic equation in standard form, we have:

`2x^2-7x=15\Rightarrow2x^2-7x-15=0`

Having that the quadratic equation, in standard form, is:

`ax^2+bx+c=0`

Then, we have that, for this case, a = 2, b = -7, and c = -15. Thus, we need to use the quadratic formula using these values.

Therefore, the value for c is c = -15.