It is given that
a+b=20 -------------------- (1)
b+c=30 -----------------------(2)
We have to calculate
3 a + 4 b +7 c
Now multiplying equation(1 )by 3,we get
3 a+ 3 b=60 ----------------------------------(3)
and Multiplying equation( 2) by 4,we get
4 b + 4 c=120 -----------------------------------(4)
Adding expression (3) and (4),we get i.e left hand side of 3 to left hand side of 4 and right hand side of 3 to right hand side of 4.
3 a+ 3 b+ 4 b+ 4 c=60+120
Adding like terms, we get
3 a+ 7 b+ 4 c =180, Which is the required solution.
Answer:
x = 35°
Step-by-step explanation:
The question is as following
cos x = sin(20 + x)° and 0° < x < 90° , find X?
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cos x = sin(20 + x)°
sin and cos are co-functions,
which means that: cos x = cos [90 - (20 + x)]
∴ x = 70 - x
∴ 2x = 70
∴ x = 35°
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Note: cos θ = sin ( 90 - θ )
Answer:
10
Step-by-step explanation:
20-(5×2)
5×2=10
20-10=10
Answer:
$38.29
Step-by-step explanation:
