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A math , need help!!
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1) Variables x and y are related by the equation ax^3 - 2 = bx^3y.When a graph of y is plotted against 1/x^3 , a straight line with gradient - 2/3 and y- intersect -7/4 is obtained . calculate the value of a and of b2) the variables x and y are related in such a way that when lg y is plotted against x, a... 顯示更多 1) Variables x and y are related by the equation ax^3 - 2 = bx^3y. When a graph of y is plotted against 1/x^3 , a straight line with gradient - 2/3 and y- intersect -7/4 is obtained . calculate the value of a and of b 2) the variables x and y are related in such a way that when lg y is plotted against x, a straight line is obtained which passes through (2,2) and (5,11). Express y in terms of x .
最佳解答:
1) Let k=1/x^3 ax^3 - 2 = bx^3y y=-2k(1/b)+(a/b) gradient= -2/3, -2(1/b)=-2/3 b=3 For (0,-7/4), -7/4=-2(0)(1/3)+(a/3) a=-21/4 2) Equation of the line: y=3(x-2)+2 y=3x-4 Put y=logy: logy=3x-4
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