Answer:
Question 8: (-4,7)
Question 10: (5,2)
Explanation:
What are equations?:
- Two mathematical expressions are equal.
- ⇒ Example; 2x + 5 = 25 is an equation, in which 2x + 5 and 25 are two expressions separated by an equal (=) sign.
What is Substitution Method?:
- The value of one variable from one equation is substituted in the other equation.
y = -2x - 1
3x - 4y = -40
Question 8:
3x - 4(-2x-1) = -40
3x + 8x + 4 = -40
11x + 4 = -40
11x = -44
x = -4
To find y we can substitute x into the equation.
y = -2(-4) -1
y = 8 -1
y = 7
(-4,7)
Question 8 Solution - (-4,7)
Question 10:
2x - y = 8
x = 5
Since this equation already given x we can substitution to find y.
2(5) - y = 8
10 - y = 8
-y = -2
y = 2
(5,2)
Question 10 Solution - (5,2)
Lenvy~