document.write( "Question 1077501: if f(x) varies directly with x^2, and f(x)=80 when x=4 find the value of f(7) \n" ); document.write( "

Algebra.Com's Answer #691988 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
I can say:
\n" ); document.write( " $\"+f%28x%29+=+k%2Ax%5E2+\"$
\n" ); document.write( "------------------
\n" ); document.write( "When $\"+x=4+\"$ , $\"+f%284%29+=+80+\"$
\n" ); document.write( " $\"+80+=+k%2A4%5E2+\"$
\n" ); document.write( " $\"+16k+=+80+\"$
\n" ); document.write( " $\"+k+=+5+\"$
\n" ); document.write( "----------------
\n" ); document.write( " $\"+f%28x%29+=+5x%5E2+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+f%287%29+=+5%2A7%5E2+\"$
\n" ); document.write( " $\"+f%287%29+=+5%2A49+\"$
\n" ); document.write( " $\"+f%287%29+=+245+\"$
\n" ); document.write( " \n" ); document.write( "

\n" );