Question

plz answer this i am not getting..........
who will answer right I will mark as brainliest
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Answer 1

Given:

Four equations containing four variables a , b , c and d.

To Find:

Value of a , b , c and d.

Answer:

We will name the squares clock wise. Please refer to attachment for naming sequence.

Let the first square be a.

Let the second square be b.

Let the third square be c.

Let the fourth square be d.

From image, we can write four equations as below:

a + b = 8 ......(1)

b - c = 5 ......(2)

c * d = 9 ......(3)

a * d = 21 ......(4)

From (1) equation, we can write:

b = 8 - a .....(5)

Substituting the value of b from (5) in (2), we get:

8 - a - c = 5

- a - c = - 3

a + c = 3

c = 3 - a .....(6)

Substituting the value of c from (6) in (3), we get:

(3 - a) * d = 9

$d = \dfrac{9}{3 - a} \: \: \: \: ........(7)$

Substituting the value of d from (7) in (4) , we get:

$\dfrac{9}{3 - a} \times a = 21$

$\dfrac{9a}{3 - a} = 21$

On cross multiplying, we get:

$9a = 63 - 21a$

$30a = 63$

$a = \dfrac{63}{30}$

$a = \dfrac{21}{10} \: \: or \: a = 2.1$

Substituting the value of a in equation (7), we get:

$d = \dfrac{9}{3 - 2.1}$

$d = \dfrac{9}{0.9}$

$d = \dfrac{90}{9}$

$d = 10$

Substituting the value of a in equation (6), we get:

c = 3 - 2.1

c = 0.9 or $\dfrac{9}{10}$

Substituting the value of a in equation (5), we get:

b = 8 - 2.1

b = 5.9 or $\dfrac{59}{10}$

Therefore, the answer is:

a = 2.1 or $\dfrac{21}{10}$

b = 5.9 or $\dfrac{59}{10}$

c = 0.9 or $\dfrac{9}{10}$

d = 10

Proof:

Substituting the values in equation (1) , (2) , (3) and (4) to prove:

a + b = 8

2.1 + 5.9 = 8 or $\dfrac{21}{10}\:+\:\dfrac{59}{10}$

8 = 8 or $\dfrac{80}{10}$

8 = 8

Hence Proved

b - c = 5

5.9 - 0.9 = 5 or $\dfrac{59}{10}\:-\:\dfrac{9}{10}$

5 = 5 or $\dfrac{59-9}{10}$

5 = 5

Hence Proved

c * d = 9

0.9.* 10 = 9 or $\dfrac{9}{10}\:\times\:10$

9 = 9

Hence Proved

a * d = 21

2.1 * 10 = 21 or $\dfrac{21}{10}\:\times\:10$

21 = 2

Hence Proved

Answer 2

Answer:

see...first one is from kristen and second from Her brother William