Which expression is equivalent to cos(4a)?
1 answer:
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Answer:
x = 6 ; y = -9
Step-by-step explanation:
8 x + 2 y = 30 ..........equ No 1
7 x + 2 y = 24......... equ No 2
8 x = 30 - 2y
∴ x =
substituting the value of x in equ No 2
7 + 2 y = 24
7 ( 30 -2 y) + 2 y × 8 = 24 × 8
7 × 30 - 14 y + 16 y = 192
210 + 2 y = 192
2 y = 192 - 210
2 y = - 18
∴ y = - 9
put y = -9 , 8 x = 30 - 2 y
8 x = 30 - 2 ( -9)
8 x = 30 - ( -18)
8 x = 48
∴ x = 6
x = 6 ; y = -9