Solve 4x − 1 = 75

The solution of 4x − 1 = 75 is x = 19.

4x - 1 = 75\ \Rightarrow\ x = 19

Explain it step by step in chat Make a short video of it

The lines y = 4x − 1 and y = 75 meet at x = 19. 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.
$4x - 1 = 75$
2
Add 1 to both sides:
$4x - 1 + 1 = 75 + 1 \ \Rightarrow\ 4x = 76$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{76}{4} \ \Rightarrow\ x = 19$
4
Check: put x = 19 back into the equation.
$4\cdot19 - 1 = 76 - 1 = 75 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 1 = 75\ \Rightarrow\ x = 19 \]
\[ 4x - 1 = 75 \]
\[ 4x - 1 + 1 = 75 + 1 \ \Rightarrow\ 4x = 76 \]
\[ \frac{4x}{4} = \frac{76}{4} \ \Rightarrow\ x = 19 \]
\[ 4\cdot19 - 1 = 76 - 1 = 75 \checkmark \]

Trying values of x in 4x − 1 = 75

x	4x − 1	Equals 75?
17	67	no
18	71	no
19	75	yes
20	79	no
21	83	no

Questions

What is x in 4x − 1 = 75?

The solution of 4x − 1 = 75 is x = 19.

How do you solve 4x − 1 = 75?

Add 1 to both sides to get 4x = 76, then divide both sides by 4 to get x = 19.

How do I check the answer?

Replace x by 19: 4(19) − 1 = 75, which is 75.

Solve 4x − 1 = 75

How to work it out

Trying values of x in 4x − 1 = 75

Questions

Similar equations