From the given graph we get that since angles 1 and 2 are complementary angles, then the angle that measures (7x+10) degrees and the angle that measures 10 degrees are also complementary angles.
Therefore:
[tex](7x+10)^{\circ}+10^{\circ}=90^{\circ}.[/tex]
Then:
[tex]7x+10+10=90.[/tex]
Adding like terms we get:
[tex]7x+20=90.[/tex]
Subtracting 20 from the above equation we get:
[tex]\begin{gathered} 7x+20-20=90-20, \\ 7x=70. \end{gathered}[/tex]
DIviding the above equation by 7 we get:
[tex]\begin{gathered} \frac{7x}{7}=\frac{70}{7}, \\ x=10. \end{gathered}[/tex]
Answer: Option B.
