X+y=18,2x+y=27
Solve the question by substitution method? Equation 1st x+y=18 equation 2nd 2x+y=27
subtract the first from the second ...
2x+y = 27
x + y = 18
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x = 9
sub into the 1st:
9+y = 18
y = 9
so x=9 and y=9
To solve the system of equations:
1. Write down the two equations:
Equation 1: X + y = 18
Equation 2: 2x + y = 27
2. Choose one of the equations to solve for one variable in terms of the other. Let's choose Equation 1 and solve for x:
X = 18 - y
3. Substitute this value of X in Equation 2:
2(18 - y) + y = 27
4. Simplify the equation:
36 - 2y + y = 27
5. Combine like terms:
-y + 36 = 27
6. Solve for y:
-y = 27 - 36
-y = -9
y = 9
7. Substitute the value of y back into Equation 1 to find the value of x:
X + 9 = 18
X = 18 - 9
X = 9
8. After solving for both variables, you find that x = 9 and y = 9.
So, the solution to the system of equations is x = 9 and y = 9.