Since <span><span>2x,</span><span>2x</span></span> does not contain the variable to solve for, move it to the right side of the equation by subtracting <span><span>2x,</span><span>2x</span></span> from both sides.<span><span><span>−y</span>=<span><span><span>−2</span>x</span>+9</span></span><span><span>-y</span>=<span><span><span>-2</span>x</span>+9</span></span></span>Multiply each one <span><span><span>−y</span>=<span><span><span>−2</span>x</span>+9</span></span><span><span>-y</span>=<span><span><span>-2</span>x</span>+9</span></span></span> by <span><span>−1</span><span>-1</span></span>Multiply each one in <span><span><span>−y</span>=<span><span><span>−2</span>x</span>+9</span></span><span><span>-y</span>=<span><span><span>-2</span>x</span>+9</span></span></span> by <span><span>−1</span><span>-1</span></span>.<span><span><span><span>−y</span>⋅<span>−1</span></span>=<span><span><span><span>−2</span>x</span>⋅<span>−1</span></span>+<span>9⋅<span>−1</span></span></span></span><span><span><span>-y</span>⋅<span>-1</span></span>=<span><span><span><span>-2</span>x</span>⋅<span>-1</span></span>+<span>9⋅<span>-1</span></span></span></span></span>make it simple <span><span><span>−y</span>⋅<span>−1</span></span><span><span>-y</span>⋅<span>-1</span></span></span>.Multiply some more. <span><span>−1</span><span>-1</span></span> by <span><span>−1</span><span>-1</span></span> to get <span>11</span>.<span><span><span>1y</span>=<span><span><span><span>−2</span>x</span>⋅<span>−1</span></span>+<span>9⋅<span>−1</span></span></span></span><span><span>1y</span>=<span><span><span><span>-2</span>x</span>⋅<span>-1</span></span>+<span>9⋅<span>-1</span></span></span></span></span>Multiply <span>yy</span> by <span>11</span> to get <span>yy</span>.(but Y?)<span><span>y=<span><span><span><span>−2</span>x</span>⋅<span>−1</span></span>+<span>9⋅<span>−1</span></span></span></span><span>y=<span><span><span><span>-2</span>x</span>⋅<span>-1</span></span>+<span>9⋅<span>-1</span></span></span></span></span>Simplify each stuff that you simplify. Multiply...again..... <span><span>−1</span><span>-1</span></span> by <span><span>−2</span><span>-2</span></span> to get <span>22</span>.<span><span>y=<span><span>2x</span>+<span>9⋅<span>−1</span></span></span></span><span>y=<span><span>2x</span>+<span>9⋅<span>-1</span></span></span></span></span>Multiply some more..... <span>99</span> by <span><span>−1</span><span>-1</span></span> to get <span><span>−9</span><span>-9</span></span>.<span>y=<span><span>2x</span><span>−<span>9.</span></span></span></span>
Given the movement of Dolphin has been modeled by the function: h(t)=-16t^2+26t the time taken for Dolphin to reach 5 feet will be: 5=-16t^2+26t writing the above in quadratic form ax^2+bx+c=0 we get: 16t^2-26t+5=0 solving the quadratic equation using quadratic formula we obtain: t=13/16+/-√89/16 t=0.22 sec or 1.40 sec
Factor out cosx: cosx(sinx-2)=0 cosx=0 or sinx-2=0 cosx=0 or sinx=2 the largest value of sinx is 1, sinx will never be 2, so cosx=0, x=π/2 or 3π/2 are the two answers.
