If ab=x and a/b=y, and ab does not equal zero, then a^2−b^2
A)x(y-1)(y+1)/y
B)xy-y/x
C)X^2-y^2
D)y(x^2-1/x^2)
E)(y+x)(y-x)/x
OAA
A)x(y-1)(y+1)/y
B)xy-y/x
C)X^2-y^2
D)y(x^2-1/x^2)
E)(y+x)(y-x)/x
OAA
Let a=4 and b=2.j_shreyans wrote:If ab=x and a/b=y, and ab does not equal zero, then a^2−b^2
A)x(y-1)(y+1)/y
B)xy-y/x
C)X^2-y^2
D)y(x^2-1/x^2)
E)(y+x)(y-x)/x
Then:
x = ab = 4*2 = 8.
y = a/b = 4/2 = 2.
a² - b² = 4² - 2² = 16-4 = 12. This is our target.
Now plug x=8 and y=2 into the answers to see which yields our target of 12.
Only A works
[x(y-1)(y+1)]/y = [(8(2-1)(2+1)]/2 = 12.
The correct answer is A.
