Difference between revisions of "Euclid 2020/Problem 1"

(Created page with "1. (a) If <math>x = 11</math>, what is the value of <math>\frac{3x + 6}{x + 2}</math>? (b) What is the y-intercept of the line that passes through <math>A(1, 5)</math> and <...")
 
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==Problem==
 
1.  
 
1.  
 
(a) If <math>x = 11</math>, what is the value of <math>\frac{3x + 6}{x + 2}</math>?
 
(a) If <math>x = 11</math>, what is the value of <math>\frac{3x + 6}{x + 2}</math>?
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(c) The lines with equations <math>y = 3x + 7</math>, <math>y = x + 9</math>, and <math>y = mx + 17</math> intersect at a
 
(c) The lines with equations <math>y = 3x + 7</math>, <math>y = x + 9</math>, and <math>y = mx + 17</math> intersect at a
 
single point. Determine the value of <math>m</math>.
 
single point. Determine the value of <math>m</math>.
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==Solution==
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(a) By plugging in <math>x=11</math>, we can get <math>\frac{3(11)+6}{11+2}=\frac{39}{13}=3</math>. Therefore, our answer is <math>\boxed{3}</math>
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(b) The slope of the line passing through <math>A(1, 5)</math> and <math>B(1, 7)</math> is <math>\frac{5-7}{1-1}</math> which is undefined. So, this is a vertical line, and therefore, there is no y-intercept.
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(c) By solving the system of equations <math>y=3x+7</math> and <math>y=x+9</math>, we can get <math>(x, y)=(1, 10)</math>. So, by plugging in <math>(1, 10)</math> into <math>y=mx+17</math>, we get <math>10=m+17</math>, so <math>m=-7</math>. There, our answer is <math>\boxed{-7}</math>.

Revision as of 18:40, 12 October 2025

Problem

1. (a) If $x = 11$, what is the value of $\frac{3x + 6}{x + 2}$?

(b) What is the y-intercept of the line that passes through $A(1, 5)$ and $B(1, 7)$?

(c) The lines with equations $y = 3x + 7$, $y = x + 9$, and $y = mx + 17$ intersect at a single point. Determine the value of $m$.

Solution

(a) By plugging in $x=11$, we can get $\frac{3(11)+6}{11+2}=\frac{39}{13}=3$. Therefore, our answer is $\boxed{3}$ (b) The slope of the line passing through $A(1, 5)$ and $B(1, 7)$ is $\frac{5-7}{1-1}$ which is undefined. So, this is a vertical line, and therefore, there is no y-intercept. (c) By solving the system of equations $y=3x+7$ and $y=x+9$, we can get $(x, y)=(1, 10)$. So, by plugging in $(1, 10)$ into $y=mx+17$, we get $10=m+17$, so $m=-7$. There, our answer is $\boxed{-7}$.