Question

Identify the a, b, and c values that should be substituted into the quadratic formula for the equation −9z
2
+7z+4=0.

a=7, b=4, c=9

a=4, b=7, c=−9

a=9, b=7, c=4

a=−9, b=7, c=4

Answer 1

To identify the values of \( a \), \( b \), and \( c \) from the quadratic equation in the standard form \( az^2 + bz + c = 0 \), we need to first rewrite the equation \( -9z^2 + 7z + 4 = 0 \) in that form.

From the given equation:

- The coefficient of \( z^2 \) (which corresponds to \( a \)) is \( -9 \).
- The coefficient of \( z \) (which corresponds to \( b \)) is \( 7 \).
- The constant term (which corresponds to \( c \)) is \( 4 \).

So the values are:

- \( a = -9 \)
- \( b = 7 \)
- \( c = 4 \)

Thus, the correct answer is:

**a = -9, b = 7, c = 4.**