Question

To solve for x in the equation 3x + 5 = 17, which of the following steps we follow?

• A. Subtract 5 on both sides of the equation. Then divide both sides of the equation by 3.
• B. Add 5 on both sides of the equation. Then divide both sides of the equation by 3.
• C. Multiply by 5 on both sides of the equation. Then divide both sides of the equation by 3.
• D. Divide both sides of the equation by 3. Then divide both sides of the equation by 3.

Answer 1

The correct option is A Subtract 5 on both sides of the equation. Then divide both sides of the equation by 3.

The given equation is 3x + 5 = 17.
If we subtract 5 on both sides of the equation, then $3x+5-5=17-5$
Or,$3x=12$. Now if we divide both sides of the equation by 3, then
$\frac{3x}{3}=\frac{12}{3}$ or, $x=4$.

We can also solve the equation by shifting all the constants to the right hand side
$3x+5=17$ so, $3x=17-5$. Note that the sign of 5 changes from + to -.
Now shift the 3 to the right hand side. Multiplication changes to division, hence, $x=\frac{12}{3}$ or $x=4$.