2 years ago

Substitution method x-7y=-9 -x+8y=10

Mathematics

1 answer:

max2010maxim [7]2 years ago

7 0

Answer:

x = -2, y=1

Step-by-step explanation:

x-7y=-9---------------------equation 1

-x+8y=10-------------------equation 2

From equation 1, make x the subject of formula

x=7y-9----------------------equation 3

substituting x=7y-9 in equation 2,

-(7y-9)+8y=10

Expanding bracket

-7y+9+8y=10

Collecting like terms

8y-7y=10-9

y=1

substituting y=1 in 3

x=7(1)-9

x=7-9

x=-2

You might be interested in

Candice won the lottery for 30000 dollars.However 20% of her money has to go to the state for taxes.How much money will she rece

Trava [24]

Answer:

She will receive $24,000 after paying taxes

Step-by-step explanation:

This question can be solved using a rule of three.

20% of her money has to go to the state for taxes. So she will receive 100-20 = 80%. $30000 is 100% = 1. How much is 80% = 0.8?

$30000 - 1

$x - 0.8

x = 30000*0.8

x = 24000

She will receive $24,000 after paying taxes

7 0

2 years ago

Simplify : (√ + √ ) (√ − √) ( + )( 2 + 2 )

jek_recluse [69]

$(\sqrt{x}+\sqrt{y})(\sqrt{x}-\sqrt{y})(x+y)(x^2+y^2)\\\\=[(\sqrt{x})^2-(\sqrt{y})^2](x+y)(x^2+y^2)\\\\=(x-y)(x+y)(x^2+y^2)\\\\=(x^2-y^2)(x^2+y^2)\\\\=(x^2)^2-(y^2)^2\\\\=x^4-y^4$

$Used:\\\\(\sqrt{a})^2=a\\\\(a-b)(a+b)=a^2-b^2\\\\(a^n)^m=a^{nm}$

6 0

2 years ago

Find a number which in which added square<br>sum will be 72.

Tom [10]

Answer:

8.48528137424^2

Step-by-step explanation:

8.48528137424x8.48528137424

= 72

7 0

3 years ago

An online store randomly samples three groups of 100 customers on which delivery method they use. The data shows the results of

masha68 [24]

The answer is 854 for sure. I did the test and got it all right.

6 0

2 years ago

Read 2 more answers

Garrett has deposited 519 in a savings account that earns interest at a rate of 4.2% compounded daily. What will the account bal

kipiarov [429]

$1059.83 Use this formula:
$A=P(1+r/n) ^{nt}$

P=principal of 519
r= your rate of 4.2% as a decimal
n=number of compounding periods; yours is daily or 365 day in a year.
t=time involved of the investment in years; yours is 17

7 0

3 years ago