Please help me on these two questions.

The value, v, of kalani’s stock investments over a time period, x, can be determined using the equation v=750(0.80)^-x. what is the rate of increase or decrease associated with this account? 20% decrease 20% increase 25% decrease 25% increase

The sum of a number and 5 times the number is 18.find the number

Which ordered pair makes both inequalities true? y< 3x-1 and y> -x+4 4,0 1,2 0,4 2,1