Solve 4x − 1 = 19

The solution of 4x − 1 = 19 is x = 5.

4x - 1 = 19\ \Rightarrow\ x = 5

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The lines y = 4x − 1 and y = 19 meet at x = 5. The solution of the equation is the x-coordinate of the point where the two sides are equal.

How to work it out

1
The goal is to get x alone. Undo the operations in the opposite order: first the subtraction, then the multiplication.
$4x - 1 = 19$
2
Add 1 to both sides:
$4x - 1 + 1 = 19 + 1 \ \Rightarrow\ 4x = 20$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{20}{4} \ \Rightarrow\ x = 5$
4
Check: put x = 5 back into the equation.
$4\cdot5 - 1 = 20 - 1 = 19 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 1 = 19\ \Rightarrow\ x = 5 \]
\[ 4x - 1 = 19 \]
\[ 4x - 1 + 1 = 19 + 1 \ \Rightarrow\ 4x = 20 \]
\[ \frac{4x}{4} = \frac{20}{4} \ \Rightarrow\ x = 5 \]
\[ 4\cdot5 - 1 = 20 - 1 = 19 \checkmark \]

Trying values of x in 4x − 1 = 19

x	4x − 1	Equals 19?
3	11	no
4	15	no
5	19	yes
6	23	no
7	27	no

Questions

What is x in 4x − 1 = 19?

The solution of 4x − 1 = 19 is x = 5.

How do you solve 4x − 1 = 19?

Add 1 to both sides to get 4x = 20, then divide both sides by 4 to get x = 5.

How do I check the answer?

Replace x by 5: 4(5) − 1 = 19, which is 19.

Solve 4x − 1 = 19

How to work it out

Trying values of x in 4x − 1 = 19

Questions

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