Math  /  Algebra

Question2. The graph of a linear function 9 passes through the points (7,4)(-7,-4) and (7,6)(7,6).
What are the slope and yy-intercept of the graph of gg ?
4. The slope is 75\frac{7}{5} and the yy-intercept is -1 . B. The slope is 75\frac{7}{5} and the yy-intercept is 1 . C. The slope is 57\frac{5}{7} and the yy-intercept is -1 . D. The slope is 57\frac{5}{7} and the yy-intercept is 1 .
3. Which ordered pair is in the solution set of y35x6y \leq \frac{3}{5} x-6 ? A. (5,4)(5,-4) B. (2,5)(-2,-5) C. (9,1)(9,1) D. (8,3)(-8,3)

Studdy Solution

STEP 1

What is this asking? We're given two points on a line and need to find the line's slope and where it crosses the y-axis.
Then, we need to figure out which point satisfies a given inequality. Watch out! Don't mix up the x and y coordinates when calculating the slope!
Also, remember that the y-intercept is where the line crosses the y-axis, meaning x=0x = 0.
For the inequality, make sure to test *all* the points, and don't forget that "less than or equal to" means the point *on* the line is also a solution!

STEP 2

1. Find the Slope
2. Find the Y-Intercept
3. Check Inequality Solutions

STEP 3

Alright, let's **find the slope**!
Remember, the slope is the "rise over run," how much the y-value changes for every change in x.
We have our two points, (7,4)(-7, -4) and (7,6)(7, 6).

STEP 4

So, our "rise" is the change in y: 6(4)=6+4=106 - (-4) = 6 + 4 = \mathbf{10}.
Our "run" is the change in x: 7(7)=7+7=147 - (-7) = 7 + 7 = \mathbf{14}.

STEP 5

Therefore, our **slope** is riserun=1014\frac{\text{rise}}{\text{run}} = \frac{10}{14}.
We can simplify this fraction by dividing both the numerator and denominator by their greatest common divisor, which is 2.
So, 1014=10÷214÷2=57\frac{10}{14} = \frac{10 \div 2}{14 \div 2} = \frac{5}{7}.
Awesome!

STEP 6

Now, let's **find the y-intercept**!
We know the equation of a line is y=mx+by = mx + b, where mm is the slope and bb is the y-intercept.
We already found our slope, m=57m = \frac{5}{7}.

STEP 7

We can plug in one of our points and our slope to solve for bb.
Let's use the point (7,6)(7, 6).
So, we have 6=577+b6 = \frac{5}{7} \cdot 7 + b.

STEP 8

Multiplying 57\frac{5}{7} by 7 gives us 5 (since 577=577=51=5\frac{5}{7} \cdot 7 = \frac{5 \cdot 7}{7} = \frac{5}{1} = 5).
So, our equation becomes 6=5+b6 = 5 + b.

STEP 9

To isolate bb, we subtract 5 from both sides of the equation: 65=5+b56 - 5 = 5 + b - 5, which simplifies to 1=b1 = b.
So, our **y-intercept** is 1\mathbf{1}!

STEP 10

Now, let's **check which ordered pair** satisfies the inequality y35x6y \leq \frac{3}{5}x - 6.
We'll test each point one by one.

STEP 11

For point A (5,4)(5, -4): 43556-4 \leq \frac{3}{5} \cdot 5 - 6.
This simplifies to 436-4 \leq 3 - 6, or 43-4 \leq -3.
This is **true**!

STEP 12

For point B (2,5)(-2, -5): 535(2)6-5 \leq \frac{3}{5} \cdot (-2) - 6.
This simplifies to 5656-5 \leq -\frac{6}{5} - 6, or 5365-5 \leq -\frac{36}{5}.
Since 365-\frac{36}{5} is equal to -7.2, we have 57.2-5 \leq -7.2.
This is **false**.

STEP 13

For point C (9,1)(9, 1): 135961 \leq \frac{3}{5} \cdot 9 - 6.
This simplifies to 127561 \leq \frac{27}{5} - 6, or 12753051 \leq \frac{27}{5} - \frac{30}{5}, which gives us 1351 \leq -\frac{3}{5}.
This is **false**.

STEP 14

For point D (8,3)(-8, 3): 335(8)63 \leq \frac{3}{5} \cdot (-8) - 6.
This simplifies to 324563 \leq -\frac{24}{5} - 6, or 32453053 \leq -\frac{24}{5} - \frac{30}{5}, which gives us 35453 \leq -\frac{54}{5}.
This is **false**.

STEP 15

The slope of the line is 57\frac{5}{7} and the y-intercept is 1 (which corresponds to answer D).
The ordered pair (5,4)(5, -4) is in the solution set of the inequality.

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