Which of the following is a situation in which an equation can not be solved using the quadratic formula

Complete question is

Which of the following is a situation in which an equation cannot be solved using the quadratic formula?  (a) The coefficient of the x^2-term is 1.

(b)The right-hand side of the equation is zero.

(c)One term of the polynomial has a degree of 3.

(d)The coefficient of the x-term is zero.

Answer :

(a) The coefficient of the x^2-term is 1 =>  we can use quadratic formula for any coefficient of x^2 term.

(b)The right-hand side of the equation is zero. => we can apply quadratic formula only when the right side of the equation =0

(c)One term of the polynomial has a degree of 3. => the highest degree of quadratic equation is 2. So we cannot apply quadratic formula for polynomial that has degree 3.

(d)The coefficient of the x-term is zero => we can apply quadratic formula but x^2 term should be there. 0 in x term does not affect the formula.

So answer is C

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."