Find the missing term. The roots of x2 − ( ____) + 34 are 5 ± 3i.
Accepted Solution
A:
ax² + bx + c ← Standard form ... Notice that there are two plus signs x² − (__) + 34 ← This is what we're given x² − mx + 34 ← This is what we know ... Now, put this in standard form x² + (-m)x + 34 ← a = 1, b = -m, c = 34
-b ± √(b²-4ac) x = ——————— ← Rewrite this as two fractions to fit the form of 5±3i 2a
-b √(b²-4ac) x = —— ± ————— ← Compare this to 5 ± 3i 2a 2a
So, -b -(-m) ——– = ——–– = 5 ⇒ m = 10a ⇒ m = 10 2a 2a