Direct Proportion functions look like this:
y=kx
'k' is the constant of proportionality and in this case its 7.5 or 15/2.
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When x=1, y=7.5
When x=2, y=15
When x=3, y=22.5
Therefore y is directly proportional to x.
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DIRECT PROPORTION EXPLAINED:
Say a football costs £7.50. If you buy one football you'll have to pay out £7.50, but if you you buy two footballs you'll have to pay out £15.00. Therefore the cost of the football(s) is directly proportional to the amount of footballs you buy. C=cost, f=football(s) and C<span>∝f, therefore C=kf, but as k=7.5, C=7.5f.
INVERSE PROPORTION EXPLAINED:
If it were to take 8 hours for one bricklayer to set up a wall, how long would it take for two bricklayers to set up a wall? The answer in this case would be 4 hours.
T=time to set up a wall
b=bricklayer(s)
Therefore T</span><span>∝1/b, and T=k/b. In this case k=8 so T=8/b.
When b=1, T=8.
When b=2, T=4.
We'd say that the time it would take for bricklayers to set up a wall would be inversely proportional to the amount of bricklayers available.</span>
To find the solution, we use the substitution method.
x+y=-1
<span>x-3y=11
</span>
x+y = -1-y
-y
x = -1-y
Now apply the value of x into the other equation.
x-3y=11
-1-y-3y = 11
Combine like terms
-4y -1 = 11
+1 +1
-4y = 12
-4y = 12
-4y/-4 = 12/-4
y = -3
Now, apply the value of Y to one equation to find x.
y = -3
x -3 = -1
+3 +3
x= 2
Now we have the value for both, x and y.
x = 2
y =-3
Final answer: A. <span>(2, −3)</span>
Yes I sure did hang the picture what about it
Move all terms to the left side and set equal to zero. Then set each factor equal to zero.
x=10,−1
