X = low-energy lamp
y = high-energy lamp
1) 4x + 5y
2) 120= 4x + 5y
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If the area is 10 square meters than double that is area of a rectangle with height = 5m and base of 4m because height • base should produce 20m^2.
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Answer:
The value of x and y that satisfy the equations is x = 2 and y = 1
Step-by-step explanation:
Given
2.5(x−3y)−3=−3x+0.5
3(x+6y)+4=9y+19
Required.
Find x and y
We start by opening all brackets
2.5(x−3y)−3=−3x+0.5 becomes
2.5x - 7.5y - 3 = -3x + 0.5
Collect like terms
2.5x + 3x - 7.5y = 3 + 0.5
5.5x - 7.5y = 3.5 ---- Equation 1
In similar vein, 3(x+6y)+4=9y+19 becomes
3x + 18y + 4 = 9y + 19
Collect like terms
3x + 18y - 9y = 19 - 4
3x + 9y = 15
Multiply through by ⅓
⅓ * 3x + ⅓ * 9y = ⅓ * 15
x + 3y = 5
Make x the subject of formula
x = 5 - 3y
Substitute 5 - 3y for x in equation 1
5.5(5 - 3y) - 7.5y = 3.5
27.5 - 16.5y - 7.5y = 3.5
27.5 - 24y = 3.5
Collect like terms
-24y = 3.5 - 27.5
-24y = -24
Divide through by - 24
y = 1
Recall that x = 5 - 3y.
Substitute 1 for y in this equation
x = 5 - 3(1)
x = 5 - 3
x = 2
Hence, x = 2 and y = 1
