MyQuestionIcon

2

You visited us 2 times! Enjoying our articles? Unlock Full Access!

Quadratic Formula

If a2+b2=13...

Question

If $a^{2} + b^{2} = 13$ and $a b = 6$ find $3 {(a + b)}^{2} - 2 {(a - b)}^{2}$ .

A

14

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

B

89

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

C

45

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

D

73

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

Open in App

Solution

The correct option is D $73$
$3 {(a + b)}^{2} - 2 {(a - b)}^{2}$
We know,
$(a + b)^{2} = a^{2} + b^{2} + 2 a b$
$= 13 + 2 (6)$
$= 13 + 12$
$= 25$
$=> (a + b) = \pm \sqrt{25}$
$=> (a + b) = \pm 5$
Again,
$(a - b)^{2} = a^{2} + b^{2} - 2 a b$
$= 13 - 2 (6)$
$= 13 - 12$
$= 1$
$=> (a - b) = \pm 1$
Putting the values, we get,
$3 {(\pm 5)}^{2} - 2 {(\pm 1)}^{2}$
$= 75 - 2$
$= 73$

Suggest Corrections

thumbs-up

0

Similar questions

a^{2} + b^{2} = 34

a b = 12

, find the value of

3 {(a + b)}^{2} + 5 {(a - b)}^{2}

.

a^{2} + b^{2} = 13

a b = 6

a^{2} - b^{2}

.

If $a^{2} + b^{2} = 14$ and $a b = 3$ , find the value of $2 (a + b)^{2} - 5 (a - b)^{2}$ .

a^{2} + b^{2} = 34

a b = 12

7 (a - b)^{2} - 2 (a + b)^{2}

.

a^{2} + b^{2} = 13

a b = 6

a - b

.

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Solving QE using Quadratic Formula

MATHEMATICS

Watch in App

explore_more_icon

Explore more

Quadratic Formula

Standard X Mathematics

Join BYJU'S Learning Program

CrossIcon