What is the Value of x?

Leave a Comment / Mathematics / By Azhar

‘X’ is used in algebra as a variable. It is often used for unknown values.

‘X’ is sometimes called ‘unknown’.

Variables can be letters, numbers, symbols, or a combination of those. It does not have to be “X”. It can be either “Y” or “W”.

For example:

x+1=5

x =5-1

x =4

Here x is unknown and the value for x is 4.

How Do You Solve for x?

Solve the equation for x by putting the variable on one side and putting all the remaining values on the other side. Calculate the result by simplifying the values.

Let’s solve the equation as

x + 5= 9

Subtract 2 from both sides

⇒ x + 5- 5 = 9 – 5

⇒ x = 4

Now, check the answer, x = 4 by back substitution in the equation. We get 4 + 5= 9.

L.H.S = R.H.S

To find an unknown angle in a triangle

Using properties of triangles or the Pythagorean theorem, we can solve for x the unknown side or angle in a triangle.

Let’s

solve for x in a triangle

△ ABC is right-angled at B with two of its legs measuring 3 units and 4 units. Find the hypotenuse x.

${(x)}^2={(4)}^2+{(3)}^2$ .

$x^2=16+9$ .

$x^2=25$ .

$x=5$ .

Solve for Equations

We solve two equations for x,

$x-4y=4$ $eq(1)$ .

$4x-y=16$ $eq(2)$ .

From eq(1)

Derive the value of x

$x=4+4y$ $eq(3)$ .

Put it $x=4+4y$ . in eq(2)

$4(4+4y)-y$ = $16$ .

$16+16y-y$ = $16$ .

$15y$ = $16-16$ .

$y=0$ .

Put $y=0$ $eq(3)$ .

$x=4+4y$ .

$x=4+4(0)$ .

$x=4$ .

$[x,y] =[4,0]$ .

Solve for x in Fractions

we simply do the cross multiplication and simplify the equation to find x.

$\frac x{20}=\frac3{10}$ .

Multiply both sides with $20$ .

$\frac x{20}\times20=\frac3{10}\times20$ .

$x=2\times2$ .

$x=4$ .

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