Answer:
[tex]\boxed{\sf x=20^o}[/tex]
Step-by-step explanation:
The two angles are complementary, which means they add up to 90°.
[tex]\boxed{\sf x^o+(3x+10^o)=90^o}[/tex]
Solving for x:-
[tex]\sf x^o+3x+10^o=90^o[/tex]
[tex]\sf 4x+10=90[/tex]
[tex]\sf 4x=80[/tex]
[tex]\sf \cfrac{4x}{4} =\cfrac{80}{4}[/tex]
[tex]\boxed{\sf x=20^o}[/tex] ← Answer
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