Question

What is the equation of a line that passes through (7, 8) and has a slope of -3?

y=−3x+29

y=3x+13

y=13x−29

y=−13x−13

Answer 1

\(\bf \begin{array}{lllll}
&x_1&y_1\\
&({\color{red}{ 7}}\quad ,&{\color{blue}{ 8}})\quad
\end{array}
\\\quad \\

slope = {\color{green}{ m}}= -3
\\ \quad \\

y-{\color{blue}{ y_1}}={\color{green}{ m}}(x-{\color{red}{ x_1}})\qquad \textit{plug in the values and solve for "y"}\\
\qquad \uparrow\\
\textit{point-slope form}\)

Answer 2

sooo y-7=m(x-8)

Answer 3

y-8=m(x-7)

Answer 4

yes.. notice that slope = m = -3

so \(\bf y-{\color{blue}{ 8}}={\color{green}{ -3}}(x-{\color{red}{ 7}})\)

Answer 5

y−8=−3(x−7),so how would i solve that

Answer 6

well, first off, distribute the -3
then add 8 to both sides
so \(\bf y-{\color{blue}{ 8}}={\color{green}{ -3}}(x-{\color{red}{ 7}})\implies y-8=-3\cdot x-(-3\cdot 7)\\ \quad \\ y-8=-3x+21

y\cancel{ -8+8 }=-3x+21+8\implies y=-3x+29\)

Answer 7

oh,ok now i see.Thanks for your help.

Answer 8

hmm looks a bit ... odd anyhow \(\bf y-{\color{blue}{ 8}}={\color{green}{ -3}}(x-{\color{red}{ 7}})\implies y-8=-3\cdot x-(-3\cdot 7)
\\ \quad \\
y-8=-3x+21\implies y=-3x+29\)

yw