Solve 4x − 15 = −19

The solution of 4x − 15 = −19 is x = -1.

4x - 15 = -19\ \Rightarrow\ x = -1

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The lines y = 4x − 15 and y = -19 meet at x = -1. 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.
$4x - 15 = -19$
2
Add 15 to both sides:
$4x - 15 + 15 = -19 + 15 \ \Rightarrow\ 4x = -4$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{-4}{4} \ \Rightarrow\ x = -1$
4
Check: put x = -1 back into the equation.
$4\cdot(-1) - 15 = -4 - 15 = -19 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 15 = -19\ \Rightarrow\ x = -1 \]
\[ 4x - 15 = -19 \]
\[ 4x - 15 + 15 = -19 + 15 \ \Rightarrow\ 4x = -4 \]
\[ \frac{4x}{4} = \frac{-4}{4} \ \Rightarrow\ x = -1 \]
\[ 4\cdot(-1) - 15 = -4 - 15 = -19 \checkmark \]

Trying values of x in 4x − 15 = −19

x	4x − 15	Equals -19?
-3	-27	no
-2	-23	no
-1	-19	yes
0	-15	no
1	-11	no

Questions

What is x in 4x − 15 = −19?

The solution of 4x − 15 = −19 is x = -1.

How do you solve 4x − 15 = −19?

Add 15 to both sides to get 4x = -4, then divide both sides by 4 to get x = -1.

How do I check the answer?

Replace x by -1: 4(-1) − 15 = -19, which is -19.

Solve 4x − 15 = −19

How to work it out

Trying values of x in 4x − 15 = −19

Questions

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