Work out 5t^2-7 when t = 4

Question

Please help! This is a question on my math homework-

 

No calculators allowed:

Work out the value of 5t^2 - 7 when t =4

 

Thankyou <3

Answer 1

QUESTION: Please help! This is a question on my math homework- No calculators allowed:
Work out the value of 5t^2 - 7 when t =4.

When t = 4, t^2 = 4^2 = 4*4 = 16.

Now replace t^2 in the original expression by 16.

5*16 - 7   --- multiply out to get,

80 - 7      --  now do a bit if arithmetic to get,

73

 

Comments

Thankyou so much! That has really helped