‘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.