Step-by-step explanation:
½ [cos(a − b) − cos(a + b)]
Using sum and difference formulas:
½ [cos a cos b + sin a sin b − (cos a cos b − sin a sin b)]
Distribute the negative:
½ (cos a cos b + sin a sin b − cos a cos b + sin a sin b)
Combine like terms:
½ (2 sin a sin b)
Simplify:
sin a sin b
4 (3x+9)-3(5y+7) =11
distribute
12x +36 -15y -21 =11
12x -15y +15 =11
subtract 15 from each side
12x -15y =-4
subtract 12x from each side
-15y= - 12x-4
divide by -15
y = -12/-15 x -4/-15
y = 4/5 x + 4/15
slope = 4/5
y intercept = 4/15
6/24 would be equal to 1/4
Step-by-step explanation:
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Remove the unnecessary brackets :
⇢ 
Combine like terms. Like terms are those which have the same base. Only coefficients of like terms can be added or subtracted.
⇢ 
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Hope I helped ! ♡
Have a wonderful day / night ! ツ
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