MHB Additional intercept form problems.

  • Thread starter Thread starter jamescv31
  • Start date Start date
  • Tags Tags
    Form
AI Thread Summary
The discussion focuses on solving two intercept form problems using the equation $$\frac{x}{a} + \frac{y}{b} = 1$$. For part a, the equation of the line through the point (-5, -7) with a y-intercept of 3 is derived, resulting in the slope m being calculated as 2, leading to the equation $$y = 2x + 3$$. In part b, the challenge lies in finding the equation with x-intercept 1/3 and y-intercept 2/5, where the correct approach involves using the "invert and multiply" rule for fractions. The final equation for part b is determined to be $$6x + 5y = 2$$ after proper manipulation. The discussion emphasizes the importance of understanding the intercept form and the correct application of mathematical rules.
jamescv31
Messages
17
Reaction score
0
Hello, I'm here for another related intercept form problem of the formula: $$\displaystyle \frac{x}{a} + \frac{y}{b} \:=\:1$$

a) Find the equation of the line passing through (-5,-7) AND with y-intercept 3.

b) Find the equation of the line passing with x-intercept 1/3 and y-intercept 2/5.

I'm not sure how this solution will be, I need this as my reference pattern.

Thank you.

Note: In letter B I couldn't figured since its a fraction and the way of having an LCD might be unsure of the correct equation so really need an informative information.

Also in Letter A, we don't have an example related for that.
 
Last edited:
Mathematics news on Phys.org
For part a) I would begin with the slope-intercept form, using the given intercept of 3:

$$y=mx+3$$

Now, use the given point $(x,y)=(-5,-7)$ and you will then be able to solve for $m$:

$$-7=m(-5)+3$$

For part b) I would use the two-intercept form you cited, and recall the "invert and multiply" rule for division by fractions:

$$\frac{c}{d/e}=c\cdot\frac{e}{d}=\frac{ce}{d}$$

Can you proceed with a) and b) now? Please feel free to post your progress. :D
 
Here's my progress, in letter a)

is it an M as slope only? not the whole equation? because the answer of my M is 2.

Then on letter B my equation answers as $$6x+5y-30=0$$?
 
jamescv31 said:
Here's my progress, in letter a)

is it an M as slope only? not the whole equation? because the answer of my M is 2.

Then on letter B my equation answers as $$6x+5y-30=0$$?

Yes, $m=2$, and so your line is:

$$y=2x+3$$

For part b) that isn't quite correct. Can you show your work so we can see where you went wrong?
 
I'm not sure on how the "invert and multiply" works.

$$x/1/3 + y/2/5 = 1

x/5 + y/6 =1 [/math] I made like a cross multiplication it becomes

[Math] 6x + 5y = 30$$ then made an LCD to obtain the
 
You use cross multiplication when you have two fractions that are equal to one another. What you want to do here is:

$$\frac{x}{1/3}+\frac{y}{2/5}=1$$

Invert and mutliply:

$$x\frac{3}{1}+y\frac{5}{2}=1$$

Multiply through by 2:

$$6x+5y=2$$
 
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Back
Top