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3 years ago

Y=5x+4 and 3x+2y=20 by using elimination

Mathematics

1 answer:

nikklg [1K]3 years ago

5 0

Answer:

Step-by-step explanation:

y = 5x + 4

-5x + y = 4 ----------------------(i)

3x + 2y = 20 --------------------(ii)

Multiply equation (i) by (-2)

(i)* (-2) 10x - 2y = -8

(ii) <u>3x + 2y = 20</u> { Now add this two equations}

13x = 12 { -2y and 2y got eliminated}

x = 12/13

Plug in value of x in (i)

-5*12/13 + y = 4

-60/13 + y = 4

y = 4 + 60/13

$y=\frac{4*13}{1*13}+\frac{60}{13}\\\\=\frac{52}{13}+\frac{60}{13}\\\\=\frac{112}{13}\\\\=8\frac{8}{13}y=$

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Solve for x.

Ivahew [28]

ANSWER

$x=\frac{2-\sqrt{10}} {3}$

or

$x=\frac{\sqrt{10}+2} {3}$

We have

$3x^2-4x-2=0$

Since we cannot factor easily, we complete the square.

Adding 2 to both sides give,

$3x^2-4x=2$

Dividing through by 3 gives

$x^2-\frac{4}{3}x= \frac{2}{3}$

Adding $(-\frac{2}{3})^2$ to both sides gives

$x^2-\frac{4}{3}x+(-\frac{2}{3})^2= \frac{2}{3}+(-\frac{2}{3})^2$

The expression on the Left Hand side is a perfect square.

$(x-\frac{2}{3})^2= \frac{2}{3}+\frac{4}{9}$

$\Rightarrow (x-\frac{2}{3})^2= \frac{10}{9}$

$\Rightarrow (x-\frac{2}{3})=\pm \sqrt{\frac{10}{9}}$

$\Rightarrow (x)=\frac{2}{3} \pm {\frac{\sqrt{10}}{3}$

Splitting the plus or minus sign gives

$x=\frac{2- \sqrt{10}} {3}$

or

$x=\frac{\sqrt{10}+2} {3}$

3 0

3 years ago

Read 2 more answers

Evaluate ab + 3c when a=-6, b=-2, and c=5

ra1l [238]

Do it step by step
ab+3c
(-6)(-2)+3(5)
A negative times a negative is positive. (-)(-)=+
12+3(5)
12+15
=27

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3 years ago

The variable in a relation who’s value depends on the value of the independent variable is called what?

Viefleur [7K]

That is called the dependent variable. It depends upon the value of the independent variable.

f(x)=y

So we can see by inspection that the dependent variable y value depends upon the input value of the independent variable x

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Mashutka [201]

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Step-by-step explanation:

Given

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