Julia spent $50 on a book. the cost of the book was $20 less than twice what she spent on a backpack. how much did the backpack cost?

Answer:

it is given that the cost of the book was $20 less than twice what she spent on a backpack, this implies that:

Cost of book = (2*cost of backpack)-20> [1]

Since, she spent $50 on the book, thus cost of the book =$50

If we substitute this in [1]

50 =( 2*cost of backpack)-20

Rearranging the terms,

50 + 20 = 2*cost of backpack

=> 70 = 2*cost of backpack

=> 70/2 = cost of backpack

=> 35 = cost of backpack

regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

explanation: