Solve 4x − 7 = −15

The solution of 4x − 7 = −15 is x = -2.

4x - 7 = -15\ \Rightarrow\ x = -2

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The lines y = 4x − 7 and y = -15 meet at x = -2. 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.
$4x - 7 = -15$
2
Add 7 to both sides:
$4x - 7 + 7 = -15 + 7 \ \Rightarrow\ 4x = -8$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{-8}{4} \ \Rightarrow\ x = -2$
4
Check: put x = -2 back into the equation.
$4\cdot(-2) - 7 = -8 - 7 = -15 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 7 = -15\ \Rightarrow\ x = -2 \]
\[ 4x - 7 = -15 \]
\[ 4x - 7 + 7 = -15 + 7 \ \Rightarrow\ 4x = -8 \]
\[ \frac{4x}{4} = \frac{-8}{4} \ \Rightarrow\ x = -2 \]
\[ 4\cdot(-2) - 7 = -8 - 7 = -15 \checkmark \]

Trying values of x in 4x − 7 = −15

x	4x − 7	Equals -15?
-4	-23	no
-3	-19	no
-2	-15	yes
-1	-11	no
0	-7	no

Questions

What is x in 4x − 7 = −15?

The solution of 4x − 7 = −15 is x = -2.

How do you solve 4x − 7 = −15?

Add 7 to both sides to get 4x = -8, then divide both sides by 4 to get x = -2.

How do I check the answer?

Replace x by -2: 4(-2) − 7 = -15, which is -15.

Solve 4x − 7 = −15

How to work it out

Trying values of x in 4x − 7 = −15

Questions

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