If $(3 + 2 i) (5 - i)$ can be written in the form of $a + i b$ , then find the value of $a$ ?

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

Open in App

Solution

The correct option is C 17
$(3 + 2 i) (5 - i) = 3 (5 - i) + 2 i (5 - i)$
$= 15 - 3 i + 10 i - 2 i^{2} = 15 + 7 i - 2 (- 1)$ , since $i^{2} = - 1$
$= 17 + 7 i$
Comparing it with $a + i b$
$∴ a = 17, b = 7$

Suggest Corrections

Similar questions

\pm

\times

\frac{1 + 2 i + 3 i^{2}}{1 - 2 i + 3 i^{2}}

a + i b,

a \cdot b =

(2 + \sqrt{2} i)^{5}

If Z = $\frac{13 - 5 i}{4 - 9 i}$ can be written in a+ib. Find the value of a+b.

\frac{1 + 2 i + 3 i^{2}}{1 - 2 i + 3 i^{2}}

a + i b,

a \cdot b =

Join BYJU'S Learning Program