Question

a line has slope -2 and contains P(3,4) and Q(-4,a). find the value of a and show work :p

Answer 1

\(\bf \begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
P&({\color{red}{ 3}}\quad ,&{\color{blue}{ 4}})\quad Q&({\color{red}{ -4}}\quad ,&{\color{blue}{ a}})
\end{array}
\\\quad \\

slope = {\color{green}{ m}}= \cfrac{rise}{run} \implies \cfrac{{\color{blue}{ y_2}}-{\color{blue}{ y_1}}}{{\color{red}{ x_2}}-{\color{red}{ x_1}}}=-2\)

solve for "a"

Answer 2

i got a-4 all over -7? what did u get @jdoe0001

Answer 3

that's correct.. but you'd still need to solve for "a"
so cross-multiply and add 4 to both sides

Answer 4

?what do u mean by that

Answer 5

\(\bf \begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
P&({\color{red}{ 3}}\quad ,&{\color{blue}{ 4}})\quad Q&({\color{red}{ -4}}\quad ,&{\color{blue}{ a}})
\end{array}
\\\quad \\

slope = {\color{green}{ m}}= \cfrac{rise}{run} \implies \cfrac{{\color{blue}{ a}}-{\color{blue}{ 4}}}{{\color{red}{ -4}}-{\color{red}{ 3}}}=-2\implies \cfrac{a-4}{{\color{red}{ -7}}}=-2\\ \quad \\
a-4={\color{red}{ -7}}\cdot 2\implies a\cancel{-4+4}=(7\cdot 2)+4\)

Answer 6

so a=18?

Answer 7

so a=18? \(\large \checkmark\)

Answer 8

thank you

Answer 9

yw