The discriminant Quiz

1. What is the discriminant of $2x^2-3x+5$?

• A. $31$
• B. $-31$
• C. $49$
• D. $-49$

2. $x^2+6x+k=0$ has equal roots. Find $k$.

• A. $36$
• B. $3$
• C. $9$
• D. $-9$

3. $mx^2-4x+1=0$ has no real roots. Which condition on $m$ is correct?

• A. $m<4$
• B. $m<-4$
• C. $m>-4$
• D. $m>4$

4. The line $y=x+k$ is a tangent to the curve $y=x^2$. Find $k$.

• A. $-\frac14$
• B. $\frac14$
• C. $-4$
• D. $4$

5. Which statement is true for $y=-x^2+2x-5$?

• A. It crosses the $x$-axis twice.
• B. It lies entirely below the $x$-axis.
• C. It touches the $x$-axis once.
• D. It lies entirely above the $x$-axis.