Step-by-step explanation:
y = f(X) = 3x - 7
3x = y + 7
x= (y +7)/3
f ^-1(x) = (x + 7)/3
Mark received £ 132
<em><u>Solution:</u></em>
Given that £440 is divided between David, Mark & Henry
Let "d" be the share of david
Let "m" be the share of mark
Let "h" be the share of henry
Total amount is 440
Therefore,
share of david + share of mark + share of henry = 440
d + m + h = 440 ------- eqn 1
<em><u>David gets twice as much as Mark</u></em>
d = 2m ----- eqn 2
<em><u>Mark gets three times as much as Henry</u></em>
m = 3h
------ eqn 3
<em><u>Substitute eqn 2 and eqn 3 in eqn 1</u></em>

Thus Mark received £ 132
To be able to graph this you need to start on -2 on the y-axis then move up 5 then 1 to the right
The dot should be on (1,3)
solution is (4, - 7 )
given the equations
y = 2x - 15 → (1)
4x + 3y = - 5 → (2)
substitute y = 2x - 15 into (2)
4x + 3(2x - 15) = - 5
4x + 6x - 45 = - 5
10x - 45 = - 5 ( add 45 to both sides )
10x = 40 ( divide both sides by 10 )
x = 4
substitute x = 4 into (1) for corresponding value of y
y = (2 × 4 ) - 15 = 8 - 15 = - 7
solution is (4, - 7 )