Let's solve for f.<span><span><span><span><span><span><span><span>fo</span>r</span>x</span><span>(0.4)</span></span>5</span><span>(<span><span>2x</span>+5</span>)</span></span>−4</span>=1</span>Step 1: Add 4 to both sides.<span><span><span><span><span><span><span><span>0.16f</span>o</span>r</span><span>x2</span></span>+<span><span>25</span><span><span><span>fo</span>r</span>x</span></span></span>−4</span>+4</span>=<span>1+4</span></span><span><span><span><span><span><span>0.16f</span>o</span>r</span><span>x2</span></span>+<span><span>25</span><span><span><span>fo</span>r</span>x</span></span></span>=5</span>Step 2: Factor out variable f.<span><span>f<span>(<span><span><span><span><span>0.8o</span>r</span><span>x2</span></span>+<span><span><span>2o</span>r</span>x</span></span>5</span>)</span></span>=5</span>Step 3: Divide both sides by (0.8orx^2+2orx)/5.<span><span><span>f<span>(<span><span><span><span><span>0.8o</span>r</span><span>x2</span></span>+<span><span><span>2o</span>r</span>x</span></span>5</span>)</span></span><span><span><span><span><span>0.8o</span>r</span><span>x2</span></span>+<span><span><span>2o</span>r</span>x</span></span>5</span></span>=<span>5<span><span><span><span><span>0.8o</span>r</span><span>x2</span></span>+<span><span><span>2o</span>r</span>x</span></span>5</span></span></span><span>f=<span>25<span><span><span><span>0.8o</span>r</span><span>x2</span></span>+<span><span><span>2o</span>r</span>x</span></span></span></span>Answer:<span>f=<span>25<span><span><span><span>0.8o</span>r</span><span>x2</span></span>+<span><span><span>2o</span>r</span><span>x</span></span></span></span></span>
