Algebraic Expressions and Identities Test

Result

Algebraic Expressions and Identities Test - 9

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

(3a − 2b + 5c)²

A
9a² + 4b² + 25c² − 12ab − 20bc + 30ac

B
9a² − 4b² − 5c² + 12ab − 20bc − 30ac

C
9a² + 4b²− 5c² − 12ab − 20bc + 30ac

D
3a² + 4b² − 5c² − 12ab − 20bc − 30ac

Solution

(a): (3a − 2b + 5c)² − (3a)²+ (−2b)² + (5c)²+ 2 {3a × (−2b) + (−2b) × (5c) + (3a × 5c)} = 9a² + 4b² + 25c² − 12ab − 20bc + 30ac.
Question 2
1 / -0

If (a² + b² + c²) = 125 and (ab + bc + ca) = 50 find the value of (a + b + c)

A
10

B
15

C
√15

D
12

Solution

a²+ b² + c² = 125 ......1 ab + bc + ca = 50 ......2 From 1 + 2 × 2 ⇒ a² + b² + c² + 2 {ab + bc + ca } = 125 + 2 × 50⇒ (a + b + c)² = 225 ⇒ a + b + c = 15
Question 3
1 / -0

If (a + b) = 2 and (a − b) = 10. Find the value of (a² + b²) = 10.

A
40

B
52

C
38

D
42

Solution

(b): (a + b)² (a − b)² = 2² + 10² ⇒ 2 {a² + b²} = 104. ⇒ a² + b² = 52.