To solve the problem of finding the discriminant of each quadratic equation, we will use the formula for the discriminant of a quadratic equation:
$$
\Delta = b^2 - 4ac
$$
where the quadratic equation is in the standard form:
$$
ax^2 + bx + c = 0
$$
Step-by-Step Solution:
#### 1) \( 2v^2 + 3v + 5 = 0 \)
- Here, \( a = 2 \), \( b = 3 \), and \( c = 5 \).
- Discriminant:
$$
\Delta = b^2 - 4ac = 3^2 - 4(2)(5) = 9 - 40 = -31
$$
-
Answer: \(\Delta = -31\)
#### 2) \( t^2 - 9t - 1 = 0 \)
- Here, \( a = 1 \), \( b = -9 \), and \( c = -1 \).
- Discriminant:
$$
\Delta = b^2 - 4ac = (-9)^2 - 4(1)(-1) = 81 + 4 = 85
$$
-
Answer: \(\Delta = 85\)
#### 3) \( 6x^2 + x - 2 = 0 \)
- Here, \( a = 6 \), \( b = 1 \), and \( c = -2 \).
- Discriminant:
$$
\Delta = b^2 - 4ac = 1^2 - 4(6)(-2) = 1 + 48 = 49
$$
-
Answer: \(\Delta = 49\)
#### 4) \( 3z^2 - 5z + 10 = 0 \)
- Here, \( a = 3 \), \( b = -5 \), and \( c = 10 \).
- Discriminant:
$$
\Delta = b^2 - 4ac = (-5)^2 - 4(3)(10) = 25 - 120 = -95
$$
-
Answer: \(\Delta = -95\)
#### 5) \( n^2 + 2n + 4 = 0 \)
- Here, \( a = 1 \), \( b = 2 \), and \( c = 4 \).
- Discriminant:
$$
\Delta = b^2 - 4ac = 2^2 - 4(1)(4) = 4 - 16 = -12
$$
-
Answer: \(\Delta = -12\)
#### 6) \( 10h^2 - h = 0 \)
- First, rewrite the equation in standard form: \( 10h^2 - h + 0 = 0 \).
- Here, \( a = 10 \), \( b = -1 \), and \( c = 0 \).
- Discriminant:
$$
\Delta = b^2 - 4ac = (-1)^2 - 4(10)(0) = 1 - 0 = 1
$$
-
Answer: \(\Delta = 1\)
#### 7) \( 4m^2 - 9 = 0 \)
- First, rewrite the equation in standard form: \( 4m^2 + 0m - 9 = 0 \).
- Here, \( a = 4 \), \( b = 0 \), and \( c = -9 \).
- Discriminant:
$$
\Delta = b^2 - 4ac = 0^2 - 4(4)(-9) = 0 + 144 = 144
$$
-
Answer: \(\Delta = 144\)
#### 8) \( g^2 - 7g + 1 = 0 \)
- Here, \( a = 1 \), \( b = -7 \), and \( c = 1 \).
- Discriminant:
$$
\Delta = b^2 - 4ac = (-7)^2 - 4(1)(1) = 49 - 4 = 45
$$
-
Answer: \(\Delta = 45\)
Final Answers:
$$
\boxed{
\begin{array}{ll}
1) & -31 \\
2) & 85 \\
3) & 49 \\
4) & -95 \\
5) & -12 \\
6) & 1 \\
7) & 144 \\
8) & 45 \\
\end{array}
}
$$
Parent Tip: Review the logic above to help your child master the concept of quadratic equations completing the square worksheet.