Answer:
Answer x = 8
Step-by-step explanation:
(5x + 4) + (8x - 18)= 90 The two angles must be complementary for this to work. Remove the brackets
5x + 4 + 8x - 18 = 90 Collect like terms
13x - 14 = 90 Add 14 to both sides
13x = 104 Divide by 13
x = 8 Answer
Check
Sin(8*8 - 18) = sin(64 - 18) = sin(46) = 0.7193
Cos(5*8 + 4) = cos(44) = 0.7193
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