Final answer:
Value of y is 110/7, to solve the equation y = 20 - 2x by substitution, substitute the value of y in another equation. Then, solve for x and substitute the value back into the original equation to find y.
Step-by-step explanation:
To solve the equation y = 20 - 2x by substitution, we need to substitute the value of y in another equation. Let's say we have another equation that includes y, such as y = 3x + 5. We can substitute the value of y in the first equation into the second equation like this:
3x + 5 = 20 - 2x
Now, solve the equation for x by combining like terms and isolating x:
5x + 2x = 20 - 5
7x = 15
x = 15/7
Substitute this value back into the first equation to find y:
y = 20 - 2(15/7)
Now, simplify and solve for y:
y = 20 - (30/7)
y = (140/7) - (30/7)
y = 110/7