Solve 7x − 15 = −43

The solution of 7x − 15 = −43 is x = -4.

7x - 15 = -43\ \Rightarrow\ x = -4

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The lines y = 7x − 15 and y = -43 meet at x = -4. 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.
$7x - 15 = -43$
2
Add 15 to both sides:
$7x - 15 + 15 = -43 + 15 \ \Rightarrow\ 7x = -28$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{-28}{7} \ \Rightarrow\ x = -4$
4
Check: put x = -4 back into the equation.
$7\cdot(-4) - 15 = -28 - 15 = -43 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 15 = -43\ \Rightarrow\ x = -4 \]
\[ 7x - 15 = -43 \]
\[ 7x - 15 + 15 = -43 + 15 \ \Rightarrow\ 7x = -28 \]
\[ \frac{7x}{7} = \frac{-28}{7} \ \Rightarrow\ x = -4 \]
\[ 7\cdot(-4) - 15 = -28 - 15 = -43 \checkmark \]

Trying values of x in 7x − 15 = −43

x	7x − 15	Equals -43?
-6	-57	no
-5	-50	no
-4	-43	yes
-3	-36	no
-2	-29	no

Questions

What is x in 7x − 15 = −43?

The solution of 7x − 15 = −43 is x = -4.

How do you solve 7x − 15 = −43?

Add 15 to both sides to get 7x = -28, then divide both sides by 7 to get x = -4.

How do I check the answer?

Replace x by -4: 7(-4) − 15 = -43, which is -43.

Solve 7x − 15 = −43

How to work it out

Trying values of x in 7x − 15 = −43

Questions

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