Solve 4x − 9 = 19

The solution of 4x − 9 = 19 is x = 7.

4x - 9 = 19\ \Rightarrow\ x = 7

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

The lines y = 4x − 9 and y = 19 meet at x = 7. 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.
$4x - 9 = 19$
2
Add 9 to both sides:
$4x - 9 + 9 = 19 + 9 \ \Rightarrow\ 4x = 28$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{28}{4} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$4\cdot7 - 9 = 28 - 9 = 19 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 9 = 19\ \Rightarrow\ x = 7 \]
\[ 4x - 9 = 19 \]
\[ 4x - 9 + 9 = 19 + 9 \ \Rightarrow\ 4x = 28 \]
\[ \frac{4x}{4} = \frac{28}{4} \ \Rightarrow\ x = 7 \]
\[ 4\cdot7 - 9 = 28 - 9 = 19 \checkmark \]

Trying values of x in 4x − 9 = 19

x	4x − 9	Equals 19?
5	11	no
6	15	no
7	19	yes
8	23	no
9	27	no

Questions

What is x in 4x − 9 = 19?

The solution of 4x − 9 = 19 is x = 7.

How do you solve 4x − 9 = 19?

Add 9 to both sides to get 4x = 28, then divide both sides by 4 to get x = 7.

How do I check the answer?

Replace x by 7: 4(7) − 9 = 19, which is 19.

Solve 4x − 9 = 19

How to work it out

Trying values of x in 4x − 9 = 19

Questions

Similar equations