Solve 4x + 15 = −25

The solution of 4x + 15 = −25 is x = -10.

4x + 15 = -25\ \Rightarrow\ x = -10

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The lines y = 4x + 15 and y = -25 meet at x = -10. 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 addition, then the multiplication.
$4x + 15 = -25$
2
Subtract 15 from both sides:
$4x + 15 - 15 = -25 - 15 \ \Rightarrow\ 4x = -40$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{-40}{4} \ \Rightarrow\ x = -10$
4
Check: put x = -10 back into the equation.
$4\cdot(-10) + 15 = -40 + 15 = -25 \checkmark$

LaTeX source of the formulas on this page

\[ 4x + 15 = -25\ \Rightarrow\ x = -10 \]
\[ 4x + 15 = -25 \]
\[ 4x + 15 - 15 = -25 - 15 \ \Rightarrow\ 4x = -40 \]
\[ \frac{4x}{4} = \frac{-40}{4} \ \Rightarrow\ x = -10 \]
\[ 4\cdot(-10) + 15 = -40 + 15 = -25 \checkmark \]

Trying values of x in 4x + 15 = −25

x	4x + 15	Equals -25?
-12	-33	no
-11	-29	no
-10	-25	yes
-9	-21	no
-8	-17	no

Questions

What is x in 4x + 15 = −25?

The solution of 4x + 15 = −25 is x = -10.

How do you solve 4x + 15 = −25?

Subtract 15 from both sides to get 4x = -40, then divide both sides by 4 to get x = -10.

How do I check the answer?

Replace x by -10: 4(-10) + 15 = -25, which is -25.

Solve 4x + 15 = −25

How to work it out

Trying values of x in 4x + 15 = −25

Questions

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