Answer:
x= -2, y= 3
Step-by-step explanation:
5. Solve the system using substitution.
4x + 5y = 7
y= 3x + 9
What variable in the top equation will you substitute the bottom equation into? y
6. Using the information from question 5, what does the top equation look like after you substitute from the bottom equation into the top equation?
4x + 5(3x+9) = 7
7. Using the equation you came up with for question 6, what does it look like simplified?
4x+5(3x+9) = 7, distribute 5 over the sum in parenthesis
4x+15x+45 = 7, subtract 45 from both sides of the equation
4x+15x+45-45 = 7-45, combine like terms
19x = -38, divide both sides by 19
x = -2
8. What is the solution to the equations from question 5?
y= 3x+9, substitute x for -2
y = 3(-2) +9
y = -6+9
y = 3
The solution for the system of equations
4x + 5y = 7
y= 3x + 9
is x= -2, y= 3
This means that the point (-2, 3) is the intersection of line 4x+5y=7 and line y=3x+9 and that point belongs to both lines.
Answer:
Below in bold.
Step-by-step explanation:
5. 4x + 5y = 7
y= 3x + 9
Substitute for y from the top equation.
5y = -4x + 7
y = (-4x + 7)/5
Substituting:
(-4x + 7)/5 = 3x + 9
6. Substituting from bottom equation, we get:
4x + 5(3x + 9) = 7
7. Simplifying the above:
4x + 15x + 45= 7
19x = -38
8. Solving equations from part 5:
(-4x + 7)/5 = 3x + 9
-4x + 7 = 15x + 45
-38 = 19x
x = -2.
Now substitute x = -2 into y = 3x + 9
y = 3(-2) + 9
= 3.
Solution is x = -2, y = 33
