Question

This is super confusing and I don't know how to solve

Answer 1

Explanation

We are given the following:

`\begin{gathered} \angle CDE\text{ }and\text{ }\angle EDF\text{ }are\text{ }supplementary \\ \angle CDE=x \\ \angle EDF=(3x+20)\degree \end{gathered}`

We are required to prove that x = 40°.

The proof goes thus:

According to step 3: Substitution in the sense of replacing the value of m∠CDE and m∠EDF.

According to step 4: Combining like terms in the sense of adding similar terms.

According to step 5: Subtraction property in the sense that you subtract 20 from both sides.

According to step 6: Division property in the sense that you divide both sides by 4.