Respuesta :
well, the x-intercept is at -4, that means, the graph touches the x-axis at -4, or when x = -4, what's the value of "y" when that happens? well, if the graph touches the x-axis, the y-value has gone all the way down to 0, and thus y = 0, therefore the point at that x-intercept is ( -4, 0 )
so, what's the equation of a line that passes through (-3,2) and (-4,0)?
[tex]\bf \begin{array}{lllll} &x_1&y_1&x_2&y_2\\ % (a,b) &({{ -3}}\quad ,&{{ 2}})\quad % (c,d) &({{ -4}}\quad ,&{{ 0}}) \end{array} \\\\\\ % slope = m slope = {{ m}}= \cfrac{rise}{run} \implies \cfrac{{{ y_2}}-{{ y_1}}}{{{ x_2}}-{{ x_1}}}\implies \cfrac{0-2}{-4-(-3)}\implies \cfrac{0-2}{-4+3} \\\\\\ \cfrac{-2}{-1}\implies 2 \\\\\\ % point-slope intercept \stackrel{\textit{point-slope form}}{y-{{ y_1}}={{ m}}(x-{{ x_1}})}\implies y-2=2[x-(-3)] \\\\\\ y-2=2(x+3)\implies y-2=2x+6\implies y=2x+8[/tex]
so, what's the equation of a line that passes through (-3,2) and (-4,0)?
[tex]\bf \begin{array}{lllll} &x_1&y_1&x_2&y_2\\ % (a,b) &({{ -3}}\quad ,&{{ 2}})\quad % (c,d) &({{ -4}}\quad ,&{{ 0}}) \end{array} \\\\\\ % slope = m slope = {{ m}}= \cfrac{rise}{run} \implies \cfrac{{{ y_2}}-{{ y_1}}}{{{ x_2}}-{{ x_1}}}\implies \cfrac{0-2}{-4-(-3)}\implies \cfrac{0-2}{-4+3} \\\\\\ \cfrac{-2}{-1}\implies 2 \\\\\\ % point-slope intercept \stackrel{\textit{point-slope form}}{y-{{ y_1}}={{ m}}(x-{{ x_1}})}\implies y-2=2[x-(-3)] \\\\\\ y-2=2(x+3)\implies y-2=2x+6\implies y=2x+8[/tex]
