1. DO NOW ... Learning Intention: To understand substitution.
Success Criteria: Substitute values into formulae.
DO NOW ...

2. Substitution into a formula involves replacing a symbol with a number.
Formulas used by 19th century British Army
Use the formula to calculate how many cannonballs are in each of the pyramids in the pictures.
Substitution into a formula involves replacing a symbol with a number.
Beta

3. Examples Calculate the value of 4x-5 when x=2
Calculate the value of x2+3x-1 when x=4
Substitute x=2 and y=3 into the expression 6x-5y
When x=2, & y=3,
6x-5y = 6×2-5×3 =
= -3
When x=4,
x2+3x-1 = ×4 -1 =
= 27
When x=2,
4x-5 = 4×2 - 5
= = 3