If we assume the number of polo shirts have been sold is x, the number of casual shirts have been sold will be 4x.
x*18+4x*9=$1080
(18+36)x=$1080
54x=$1080
x=20
The number of casual shirts have been sold is 4*20=80
10,000,000+2,000,000+400,000+30,000
Substitute y=4x to the second equation:
x^2 + (4x)^2 = 17
x^2 + 16x^2 = 17
17x^2 = 17
x^2 = 17/17
x^2 = 1
x = 1 and -1
When x=1, y=4(1) = 4
When x=-1, y=4(-1) = -4
Thus the solutions would be (1,4) and (-1,-4). That would correspond to D. and A.
9514 1404 393
Answer:
√42 ≈ 6.48074
Step-by-step explanation:
Put the values in place of the corresponding variables and do the arithmetic.

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42 = 2·3·7 is not a perfect square, nor does it have any perfect square factors. Its square root is irrational.