The quadratic formula

Solve any quadratic, including ones that do not factor, and simplify the radical answers.

Standards:A-REI.B.4.b

Try it: three questions

Real questions from the practice bank. Tap an answer to check it.

Question 1 of 3

A ball is launched upward from ground level. Its height h (in meters) after t seconds is given by h = –5t² + 20t. At what time does the ball reach a height of 15 meters on its way down?

Question 2 of 3

A ball is thrown upward from ground level. Its height h (in meters) after t seconds is given by h = –5t² + 20t. At what time does the ball return to ground level?

Question 3 of 3

A rectangular garden has a length that is 3 meters more than its width. If the area is 28 square meters, what is the width?

How this fits in

The quadratic formula is one skill in the Quadratic Equations unit. Students read the unit lesson, then earn a bronze, silver, or gold medal on their last 10 answers. Medals never go down. A mastered unit comes back for review after 1, 3, 7, 16, and 35 days so it stays learned.

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