Further exercises: Linear functions

Draw the function $y=-3x$

Mirror the line along the $x$-axis.

Read the new equation of the function.

It is: $y=3x$

Move the straight line up by 2 units.

The $y$-axis intercept has changed.

Read off the new function equation.

Answer: The straight line mirrored on the $x$-axis and shifted upwards by $2$ units has the equation $y=3x+2$

Solution for b)

When mirroring on the $x$-axis, the function term is multiplied by $(-1)$.

 $y=(-1)\cdot (-3x)=3x$

Thus the equation of the mirrored straight line is $y=3x\text{}$

Move this straight line up by 3.

This corresponds to the $y$-axis intercept $t\Rightarrow$ $t=2$

Answer: The new line equation is:

$y=3x+2$