My little cuz need help can you help her please Its Eight grade math

Solve the equation by using substitution

4x-2y=18
y=5x

Adriveway is 60-feet long by 6-feet wide. the length and width of the driveway will each be increased by the same number of feet. the following expression represents the perimeter of the larger driveway: (x + 60) + (x + 6) + (x + 60) + (x + 6) which expression is equivalent to the expression for the perimeter of the larger driveway? a) 2(x + 66) b) 4x + 33 c) 4(x + 33) d) 4(x + 132)

Plzzz plzz maths ! quadratic sequences =an^2+bn 1) 1,6,15,28,45 2)5,18,39,68,105 3) 1,8,21,40,65 4) 7,24,51,88,135 5) -1,2,9,20,35

What is the number 321,000,000 in scientific notation? also what is the number? ?