# Thread: given that g is a linear function with slope =-4 and g (-2)=2, write the equation tha

1. ## given that g is a linear function with slope =-4 and g (-2)=2, write the equation tha

given that g is a linear function with slope =-4 and g (-2)=2, write the equation that defines g.

need ur help guys...i'm completely lost

2. Originally Posted by alessandromangione
given that g is a linear function with slope =-4 and g (-2)=2, write the equation that defines g.

need ur help guys...i'm completely lost
point-slope form ...

$\displaystyle y - y_1 = m(x - x_1)$

$\displaystyle y - g(-2) = -4[x - (-2)]$

3. why in the last part u put m(x-(-2)) ? isn't x1 2 ?

4. Originally Posted by alessandromangione
why in the last part u put m(x-(-2)) ? isn't x1 2 ?
No, $\displaystyle g(-2)=2$ therefore,

$\displaystyle y - g(-2) = -4[x - (-2)]$

$\displaystyle y - 2 = -4[x - (-2)]$

5. Also, any linear function can be written g(x)= mx+ b where "m" is the slope. You are told that m= -4 so g(x)= -4x+ b. Now put x= -2, g(x)= g(-2)= 2 and solve for b.

g(-2)= 2 means that x= -2, y= 2.