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3 years ago

3x + y =11 and 6x + 3y = 24 solved by elimination

Mathematics

1 answer:

Svetradugi [14.3K]3 years ago

4 0

Y=2 x=3 double check is at bottom but cut off

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-3x - y = 0 and -8x +5y=7

andrezito [222]

Answer:

-23x = 7

Step-by-step explanation:

-3x - y =0

×5. ×5 ×5

-15x -5y = 0

-8x +5y = 7

-15x -5y -0

-23x = 7

8 0

3 years ago

Which expression represents the number 2i4−5i3+3i2+−81‾‾‾‾√ rewritten in a+bi form?

vichka [17]

Answer:

The expression $-1+14i$ represents the number $2i^4-5i^3+3i^2+\sqrt{-81}$ rewritten in a+bi form.

Step-by-step explanation:

The value of $i$ is $i=\sqrt{-1}[tex] or [tex]i^{2}=-1[\tex].Now [tex]i^{4}$ in term of $i^{2}[\tex] can be written as, [tex]i^{4}=i^{2}\times i^{2}$

Substituting the value,

$i^{4}=\left(-1\right)\times \left(-1\right)$

Product of two negative numbers is always positive.

$\therefore i^{4}=1$

Now $i^{3}$ in term of $i^{2}[\tex] can be written as, [tex]i^{3}=i^{2}\times i$

Substituting the value,

$i^{3}=\left(-1\right)\times i$

Product of one negative and one positive numbers is always negative.

$\therefore i^{3}=-i$

Now $\sqrt{-81}$ can be written as follows,

$\sqrt{-81}=\sqrt{\left(81\right)\times\left(-1\right)}$

Applying radical multiplication rule,

$\sqrt{ab}={\sqrt{a}}\sqrt{b}$

$\sqrt{\left(81\right)\times\left(-1\right)}={\sqrt{81}}\sqrt{-1}$

Now, $\sqrt{\left(81\right)=9$ and $\sqrt{-1}}=i$

$\therefore \sqrt{\left(81\right)\times\left(-1\right)}=9i$

Now substituting the above values in given expression,

$2i^4-5i^3+3i^2+\sqrt{-81}=2\left(1\right)-5\left(-i\right)+3\left(-1\right)+9i$

Simplifying,

$2+5i-3+9i$

Collecting similar terms,

$2-3+5i+9i$

Combining similar terms,

$-1+14i$

The above expression is in the form of a+bi which is the required expression.

Hence, option number 4 is correct.

5 0

3 years ago

James spent $(2y2 + 6). He bought notebooks that each cost $(y2 − 1).

CaHeK987 [17]

The expression to find the number of notebooks James bought would be written as:

Number of notebooks = total spent / cost per item

Number of notebooks = (2y^2 + 6) / (y^2 − 1)

If y = 3, then the number of notebooks bought would be:

Number of notebooks = (2y^2 + 6) / (y^2 − 1)
Number of notebooks = (2(3)^2 + 6) / (3^2 − 1)
Number of notebooks = 3 pieces

7 0

2 years ago

The ratio of three numbers is 4 : 3 : 1. the sum of the numbers is 64. the greatest of these three numbers is

DanielleElmas [232]

Total value of ratio = 4+3+1 = 8

value of 1 unit = 64/8 = 8

numbers are 4(8), 3(8), 1(8) = 32, 24, 8

so, the greatest number is 32

3 0

3 years ago

Read 2 more answers

Round 78482 to the nearest thousand

shtirl [24]

Answer:

78,000

Explanation:

8,000 is in the thousands place, the 4 in the hundreds place is too low to round it up to 9,000, so it gets rounded down to 78,000.

6 0

2 years ago