Solve 5x − 7 = 28

The solution of 5x − 7 = 28 is x = 7.

5x - 7 = 28\ \Rightarrow\ x = 7

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The lines y = 5x − 7 and y = 28 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.
$5x - 7 = 28$
2
Add 7 to both sides:
$5x - 7 + 7 = 28 + 7 \ \Rightarrow\ 5x = 35$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{35}{5} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$5\cdot7 - 7 = 35 - 7 = 28 \checkmark$

LaTeX source of the formulas on this page

\[ 5x - 7 = 28\ \Rightarrow\ x = 7 \]
\[ 5x - 7 = 28 \]
\[ 5x - 7 + 7 = 28 + 7 \ \Rightarrow\ 5x = 35 \]
\[ \frac{5x}{5} = \frac{35}{5} \ \Rightarrow\ x = 7 \]
\[ 5\cdot7 - 7 = 35 - 7 = 28 \checkmark \]

Trying values of x in 5x − 7 = 28

x	5x − 7	Equals 28?
5	18	no
6	23	no
7	28	yes
8	33	no
9	38	no

Questions

What is x in 5x − 7 = 28?

The solution of 5x − 7 = 28 is x = 7.

How do you solve 5x − 7 = 28?

Add 7 to both sides to get 5x = 35, then divide both sides by 5 to get x = 7.

How do I check the answer?

Replace x by 7: 5(7) − 7 = 28, which is 28.

Solve 5x − 7 = 28

How to work it out

Trying values of x in 5x − 7 = 28

Questions

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