Answer:
a = 3, b = - 7
Step-by-step explanation:
Substitute x = 2 into the equation and equate to 5, that is
a(2)² + b = 5
4a + b = 5 → (1)
Substitute x = 3 into the equation and equate to 20
a(3)² + b = 20
9a + b = 20 → (2)
Subtract (1) from (2) term by term to eliminate b
(9a - 4a) + (b - b) = (20 - 5), that is
5a = 15 ( divide both sides by 5 )
a = 3
Substitute a = 3 into either of the 2 equations and solve for b
Substituting in (1)
4(3) + b = 5
12 + b = 5 ( subtract 12 from both sides )
b = - 7
