My Land, this is the solution:
Step 1: Let's factor the quadratic equation:
2z² + 19z - 21
(2z - 2 ) (z + 10.5) = 0
These are the operations to show it works:
2z * z = 2z²
2z * 10.5 - 2 * z = 21z - 2z = 19z
-10.5 * 2 = -21
Thus, the factors are right.
Step 2: Now, let's calculate the roots of the equation, as follows:
First root:
2z - 2 = 0
Dividing by 2:
z - 1 = 0
z1 = 1
Second root:
z + 10.5 = 0
z2 = -10.5
• The factors are (2z - 2) and (z + 10.5)
,
• The roots are -10.5 and 1