The opposite of 7 on a number line would be -7 because if you look at 0 as a mirror, then the opposite of 7 is -7.
Direct variations take the form y=kx. We need to solve for y in order to find k.
<span>3x+5y=0 </span>
<span>5y=-3x </span>
<span>y=(-3/5)*x </span>
<span>k=-3/5.</span>
The cosine repeats itself every 360 degrees, and it mirrors at 0 and 180 degrees. It inverts around 90 and 270.
So without using a calculator, you can tell that:
cos(520)=cos(520-360)=cos(160)
cos(160) = cos(180-20) = cos(180+20) = cos(200)
cos(160) is NOT equal to cos(20), it would be -cos(20).
cos(160) = -cos(20) = -cos(-20)
So C is the only one unequal.
The equation is y= 1/4x + 3
