Answer - D.
you basically find the equation of the line first and eliminate the wrong answers...
Strategy: before u do any of this, label your coordinates as (X1,Y1) and (X2,Y2) and u can choose any of ur points to be as x1 or x2 or y1 or y1...
basically, I'll choose (6,7) as (x1,y1) and (2,-1) as (x2,y2). SO,
First you have to find the gradient (m) of the line.
you do this by using the formula m = Y2-Y1 / X2-X1 (where '/' is division sign) ....
Put the numbers in their respective places and your gradient will be 2x. we put the x after our number to represent it as a gradient as the straight line formula is y = mx+c and you've found the m.
NOW.
use the formula Y-Y1=m(x-x1) to find the equation of the line.Again u can use any Y1 and X1 here but remember your m is 2
replace the digits and solve...Hopefully you'll get sth like this if you use the points (6,7):
Y-7 = 2(x-6) ....
y=2x-12+7...
Y=2x-5! <<<< this is your straight line equation!
Now all u gotta do is rearrange all your options into y = mx+c.
D. is incorrect as it gives us y=2x+5 and not y = 2x-5 unlike the others
Hope you get it!
Answer:
$72.90 is the interest earned
Step-by-step explanation:
The appropriate formula is i = prt, where r is the annual interest rate expressed as a decimal fraction.
Here, i = ($270)(0.09)(3 yr) = $72.90 is the interest earned
Answer:
4r^3+8r^2-5r-10
= 4r^2(r+2)-5(r+2) [Factorise out like terms; distributive law of multiplication to check]
=(4r^2-5)(r+2) [Combine expressions]
4 grams sample will be left after 1 year
Step-by-step explanation:
The decay function for percentage decay is given by:
Here,
a is the initial value
r is the rate
x is the number of time periods
Given
Initial value = 100 grams
Rate = 6% = 0.06
Time = 1 year = 52 weeks
Putting the values in the formula
Hence,
4 grams sample will be left after 1 year
Keywords: Decay, percentage
Learn more about decay functions at:
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