Checkpoint: the form, the roots and the formula

Which of these is x² = 7x − 10 tidied into standard form?

• `x² − 7x + 10 = 0`
• `x² − 7x = 10`
• `x² + 7x − 10 = 0`

Which value is a root of x² − x − 6 = 0?

• 3
• 4
• 2

x² = 5x was solved by dividing both sides by x, giving x = 5. What did the dividing lose?

• The root x = 1
• The root x = 0
• Nothing — 5 is the only root

What is b² − 4ac for 2x² − 5x + 2 = 0?

• `−25 − 16 = −41`
• `25 − 16 = 9`
• `25 − 8 = 17`

Without solving, what does the decider say about x² + 3x + 4 = 0?

• No real root, because `b² − 4ac = 9 − 16 = −7`
• One repeated root, because a and c are both positive
• Two distinct real roots, because b is positive