Substitution is where we first Isolate one of the unknowns, express it in terms of the other unknown, and replace the isolated unknown with the other unknown in another equation. So that each time we only need to deal with one unknown. I think you'll get a better idea here:
First name these 2 equations with 1 and 2.
4x + 5y = 7 (1)
y = 3x + 9 (2)
Since y is already isolated in (2), so we can skip the isolation step and continue to substitute.
Substitute (2) into (1).
4x + 5(3x+9) = 7
Expand.
4x + 15x + 45 = 7
Group.
19x + 45 = 7
Shift +45 to the other side and turn it into -45.
19x = 7 - 45
19x = -38
Shift x19 to the other side, turn it into /19.
X = - 38/19
X = - 2
Now we solved x already, we can just substitute x= - 2 back to equation (2).
y = 3(-2) + 9
y = - 6 + 9
y = 3
So, the answers are
x = - 2
y = 3
The value of x when y = 14 is 8.4
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<h3>How to solve variation ?</h3>
y, varies directly as x. Therefore,
y ∝ x
Therefore,
y = kx
where
- k =constant of proportionality
Therefore,
10 = 6k
k = 10 / 6
k = 5 / 3
Hence, when y = 14
y = kx
14 = 5 / 3 x
cross multiply
42 = 5x
x = 42 / 5
x = 8.4
learn more on variation here: brainly.com/question/20707320
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The answer is not applicable. theres not enough information. -fvmousskaylaa
Answer: y=4x-9
explanation: move the -4x over to the other side and it becomes positive 4x and -9 stays the same.
Answer:
Step-by-step explanation:
Vertex form: 
where:
is the vertex
is some constant
Given:
- vertex = (-4, -1)
- point on parabola = (-2, -3)
Substitute given values into the formula to find :
Therefore, the equation of the parabola is:
