4a-8=28
add 8 to both sides to start to isolate the variable (a)
-8+8 cancels each other out
28+8=36
4a=36
to completely isolate the variable divide both sides by 4
4a÷4=a
36÷4=9
a=9
Answer:
D
Step-by-step explanation:
Given the 2 equations
y = x - 5 → (1)
y = x² - 5x + 3 → (2)
Substitute y = x² - 5x + 3 into (1)
x² - 5x + 3 = x - 5 ← subtract x - 5 from both sides
x² - 6x + 8 = 0 ← in standard form
(x - 2)(x - 4) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 2 = 0 ⇒ x = 2
x - 4 = 0 ⇒ x = 4
Substitute each of these values into (1) for corresponding values of y
x = 2 → y = 2 - 5 = - 3 ⇒ (2, - 3 )
x = 4 → y = 4 - 5 = - 1 ⇒ (4, - 1 )
