Class 9th math Review Exercise 3 solution english PCTB

Question 13: Consider the function \(g(x)=mx^2+n\), where \(m\) and \(n\) are constant numbers. If \(g(4)=20\) and \(g(0)=5\) , find the values of \(m\) and \(n\).

Solution:

\(g(x)=mx^2+n\)

\(g(4)=m(4)^2+n\)

\(g(4)=16m+n\)

\(16m+n=20\)\(\ \_\_\_\_\_\_\ (1)\)\(\quad \because g(4)=20\)

\(g(0)=m(0)^2+n\)

\(g(0)=n\)

\(n=5\)\(\quad \because g(0)=5\)

Put value of \(n\) in equation \((1)\), we have

\(16m+5=20\)

\(16m=20-5\)

\(16m=15\)

\(m=\frac{15}{16}\)

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