use substitutio method

y+x=7
3x+y=15

y+x=7

3x+y=15

y = 7 - x

3x + 7 - x = 15

2x = 8

x = 4

Take it from there.

a bucket is 44cm in diameter at the top and 24cm at diameter at the bottom.Find its capacity in litres if its 36cm deep

y+4=7

y=3
(3×4)+y=15
12+y=15
y=3
answer=....x=4 and y=3

To solve the system of equations using the substitution method, we will solve one equation for one variable and substitute it into the other equation.

Let's solve the first equation, y + x = 7, for y:

y = 7 - x

Now, substitute this expression for y into the second equation, 3x + y = 15:

3x + (7 - x) = 15

Simplify the equation:

3x + 7 - x = 15

Combine like terms:

2x + 7 = 15

Subtract 7 from both sides:

2x = 8

Divide both sides by 2:

x = 4

Now that we have found the value of x, we can substitute it back into the first equation to find the value of y:

y + 4 = 7

Subtract 4 from both sides:

y = 7 - 4

y = 3

So, the solution to the system of equations is x = 4 and y = 3.