Final answer:
To solve the system of equations у= 10 – 3х and 7x-y= 8 by substitution, first solve one equation for either y or x, and then substitute that value into the other equation.
Step-by-step explanation:
To find the solution to the system of equations у= 10 – 3х and 7x-y= 8 by substitution, we need to solve one of the equations for either y or x, and then substitute that value into the other equation.
Let's solve the first equation, у= 10 – 3х, for y: y = 10 - 3x. Now we can substitute this expression for y into the second equation, 7x - y = 8: 7x - (10 - 3x) = 8.
Simplifying this equation, we get: 7x - 10 + 3x = 8. Combining like terms: 10x - 10 = 8.
Adding 10 to both sides: 10x = 18. Dividing both sides by 10: x = 1.8. Now we can substitute this value for x back into the first equation to find the value of y: y = 10 - 3(1.8) = 10 - 5.4 = 4.6.
Therefore, the solution to the system of equations у= 10 – 3х and 7x-y= 8 by substitution is x = 1.8 and y = 4.6.