All categories

2 years ago

Solve 7x+3y=8 and 4x-y=-9 simultaneously

Mathematics

1 answer:

Jobisdone [24]2 years ago

5 0

Answer: x = -1 and y = 5

Step-by-step explanation:

7x + 3y = 8 ........................... equation 1

4x - y = - 9 ............................ equation 2

Solving the simultaneous linear equation by substitution method , make y the subject of the formula from equation 2 , we have

y = 4x + 9 ............................. equation 3

substitute y = 4x + 9 into equation 1 , we have;

7x + 3 ( 4x + 9 ) = 8

7x + 12x + 27 = 8

19x + 27 = 8

subtract 27 from both sides

19x = -19

divide through by 19

x = -1

substitute x = -1 into equation 3 , we have

y = 4 ( -1) + 9

y = -4 + 9

y = 5

Therefore :

x = -1 and y = 5

You might be interested in

In this pattern 9,12,15,18,21 what is the next number

laiz [17]

It is 24. You just add 3 each time. hope it helps!

8 0

2 years ago

Need help asap important! thanks so much!

a_sh-v [17]

Answer:

You would have $343.37 at the end of the 2 years.

Step-by-step explanation:

Interest earned is like bonus money the bank pays you just for keeping money

$\mathrm{Compund\:Interest\:Formula}:\quad A = P { \left( 1+ \dfrac{ r }{ n } \right) }^{ nt }$

P: the starting balance of the account (also called initial deposit, or principal)

A: the new balance in the account after N years.

t: the number of years or time

r: the interest rate, (in decimal form)

n: the number of times the interest is compounded each year.

Annually = each year = 1

P =$300, r = 7%, t = 2, n = 1, A = ?

Substitute the numbers into the "Compound Interest Formula".

$A = 300 { \left( 1+ \dfrac{ 0.07 }{ 1 } \right) }^{ 1 \times 2 }$

$\mathrm{Anything\:divided\:by\:1\:gives\:itself}$

$A = 300 { \left( 1+0.07 \right) }^{ 1 \times 2 }$

$\mathrm{Add\:1\:and\:0.07\:to\:get\:1.07}$

$A = 300 \times { 1.07 }^{ 1 \times 2 }$

$\mathrm{Multiply\:1\:and\:2\:to\:get\:2}$

$A = 300 \times { 1.07 }^{ 2 }$

$\mathrm{Calculate\:1.07\:to\:the\:power\:of\:2\:and\:get\:1.1449}$

$A = 300 \times 1.1449$

$\mathrm{Multiply\:300\:and\:1.1449\:to\:get\:343.47}$

$A = 343.47$

So you would have $343.37 at the end of the 2 years.

Look at the chart

$\mathrm{Year}\quad \mathrm{Year\: Interest}\quad \mathrm{Total\:Interest}\quad \mathrm{Balance}\\\quad1\quad\quad\quad $21.00\quad\quad\quad\quad $21.00\quad\quad\quad\quad $321.00\\\quad2\quad\quad\quad $22.47\quad\quad\quad\quad $43.47\quad\quad\quad\quad $343.47$

8 0

2 years ago

Which inequality is true? Use the number line to help.

jolli1 [7]

Answer:

c. -1.5 < -0.5

Step-by-step explanation:

a. -1.5 > 0.5 . . . . false

b. -0.5 > 0 . . . . . false

c. -1.5 < -0.5 . . . TRUE

d. 1/2 > 0.5 . . . . false (these are the same number) 1/2 = 0.5

_____

In order on the number line from left to right, you will see ...

(left end) ... -1.5 ... -0.5 ... 0 ... 0.5 ... (right end)

The inequality relation appropriate to these is ...

(number on the left) < (number on the right)

Of course, this can be swapped around so you have ...

(number on the right) > (number on the left)

4 0

2 years ago

Let p = log10 x, q = log10 y, and r = log10 z. (The 10s are base numbers.)

KatRina [158]

Answer:

(p / q^2 √r)

Just make x, y, z into p, q, r.

Very simple!

4 0

2 years ago

Cara and Jena, working together, can clean the house in 4

kirill115 [55]

Answer:

$\frac{4}{3}$ hrs/house

Step-by-step explanation:

Rate is the amount of work done per unit of time;

Let Cara's rate = C

Let Jena's rate = J

C + J = 4 ------ i

Now;

Working alone:

Jena takes twice as long as Cara

J = 2C ---- i

How long does it take Cara to clean a house alone

C + J = 4

J = 2C

C + 2C = 4

3C = 4

C = $\frac{4}{3}$ hrs/house

6 0

2 years ago