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3 years ago

9

Evaluate 2x when x = 9

1 answer:

Wewaii [24]3 years ago

4 0

Answer:

18

Step-by-step explanation:

Since x = 9 you would multiply the 2 numbers together.

9 x 2 = 18

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PLEASE HELP HURRY!!!!!!!

Charra [1.4K]

As it has been given that $x=4+5i$ , $y=2-9i$ .

We need to find the value of the following:

(i) $4x-y$ , substituting the value of 'x' and 'y' in the expression, we get:

$4(4+5i)-(2-9i)=4\times 4+4\times 5i-2+9i=16+20i-2+9i$

$=14+29i$

So, $4x-y=14+29i$

(ii) $-x+3y$ , substituting the value of 'x' and 'y' in the expression, we get:

$-(4+5i)+3(2-9i)=-4-5i+3\times 2-3 \times 9i=-4-5i+6-27i$

$=2-32i$

So, $-x+3y=2-32i$

(iii) $x \times y$ , we need to substitute the value of 'x' and 'y' in the expression, for this, we can use distributive property of multiplication that says,

$a(b+c)=a \times b+ a \times c$

Using the distributive property of multiplication:

$(4+5i)\times(2-9i)=4 \times 2-4 \times 9i+5i \times 2-5i \times 9i$

$=8-36i+10i-45i^2$

Now, we know that $i \times i=i^2=-1$

We get, $8-36i+10i-45 \times (-1)=8-26i+45$

$=8+45-26i=53-26i$

Therefore, $x \times y$ = $53-26i$ .

(iv) We have, $2x \times y$ , we need to substitute the value of 'x' and 'y' in the expression, we get:

$2(4+5i)\times (2-9i)$

Again, we can use distributive property of multiplication that says,

$a(b+c)=a \times b+ a \times c$

So,

$2(4+5i) \times (2-9i)=2\times 4+2 \times 5i\times(2-9i)$

$=8+10i \times(2-9i)=8\times 2-8 \times 9i+10i \times 2-10i \times 9i$

$=16-72i+20i-90i^2$

since, $i^2=-1$

we get,

$16-72i+20i-90 \times (-1)=16-52i+90$

$=106-52i$

Therefore,

$2x \times y=106-52i$

7 0

4 years ago

Read 2 more answers

Find two positive numbers whose difference is 7 and whose product is 2438.

GaryK [48]

Answer: 348 and 355

Step-by-step explanation:

Let two positive numbers are x and y

so,

when the difference is 7 then equation will become

x-y=7 Eq(1)

when product is 2439 then equation will become

x*y=2438 Eq (2)

By rearranging Equation (2)

x= 2438/y Eq(3)

Now put the value of x as in eq (3) in eq(1) to get y's value

(2438/y)-y=7

(2438-1)/y =7

2437 / y =7

2437/7 =y

y=348.14 approx 348

Put the value of y in Eq(1) for x

x-348=7

x=7+348

x=355

so the two positve numbers are 355 and 348

For Check

x-y=7

355-348=7

7=7

5 0

3 years ago

The polynomial given below has _____ root(s).2x2 + 5x + 2

Nastasia [14]

2x^2 + 5x + 2 = 0
(x + 2)(2x + 1) = 0
x = -2 x = - 1/2
Letter C

8 0

3 years ago

A student cuts pieces of ribbon to decorate a banner the first piece of ribbon is 24 inches long. The next piece of ribbon is on

kumpel [21]

Answer:

Option D) 47.25 in

Step-by-step explanation:

we know that

The equation of a exponential decay function is equal to

$y=a(1-r)^x$

where

y is the total length

x is the number of pieces of ribbon

a is the initial value

r is the rate of change

we have

$a=24\ in\\r=50\%=50/100=0.50$

substitute

$y=24(1-0.50)^x$

$y=24(0.50)^x$

we have that

For x=0 -----> $y=24\ in$

For x=1 ----> $y=24(0.50)^1=12\ in$

For x=2 ----> $y=24(0.50)^2=6\ in$

For x=3 ----> $y=24(0.50)^3=3\ in$

For x=4 ----> $y=24(0.50)^4=1.5\ in$

For x=5 ----> $y=24(0.50)^5=0.75\ in$

Adds the length of the first 6 pieces of ribbon

$24+12+6+3+1.5+0.75=47.25\ in$

7 0

3 years ago

Does anyone know this?

DENIUS [597]

Answer:

1/4

Step-by-step explanation:

(6-5)/4

= 1/4

4 0

4 years ago

Read 2 more answers