Solving Equation
Solve:
3x+5=20
x=5
A number plus 7 equals 15. What is the number?
n=8
Solve:
2x+3>11
x>4
You need at least 30 points to win a prize. You already have 12.
Write and solve an inequality to find how many more points you need.
When should we flip our inequalities symbol?
When you multiply or divide negative number.
Solve:
4x+29=2x-45
x=-37
Sam bought 3 notebooks and a $4 pen for $19 total.
Write and solve an equation to find the cost of one notebook.
n=5
Solve:
6−2x<10
x>-2
You want to save at least $250. You already saved $40 and plan to save $12 per week.
Write and solve an inequality for the number of weeks needed.
at least 17.5 weeks, or 18 weeks.
If I have fraction as my coefficient what should I do to cancel out that?
Multiply it reciprocal
(n-7)/9=-3
n=-20
A movie ticket costs $9.50. A popcorn costs $x.
Buying 2 tickets and 1 popcorn costs $28.
Write and solve an equation to find the popcorn price.
x=9
-2(5v-12)>6-v
v<2
A taxi costs $5 plus $1.80 per mile.
You have no more than $30.
Write and solve an inequality to find how far you can ride.
No more than 13.89 mile.
When we have to use open circle and closed circle in graphing?
≤, ≥ (closed circle)
<, > (open circle)
Solve:
3/4 (4x+12)=2 (x+14)
x=19
Ryan is building a tree house. He has 18 feet of wood to use. He uses three-fourths of a foot of wood to make each step for the ladder. If he has 15 feet of wood left, how many ladder steps did he make?
4 steps
7-3(6c+14)>5(1-2c)
c<-5
Kevin is taking a two-part test in math class. Part 1 multiple choice and worth 55 points. Part 2 word problem and worth 25 points. He must earn at least 70 points to pass the class. If his teacher already graded part 2 and he earned 10 points, how many points will he need to earn on part 1?
He failed because the total score for Part 1 was less than 60.
If I got a solution 6>x. Which direction should my graph go?
Left
Solve:
2/5 (10x+25)-3x=4 (2x-1)+7
x=1
Mark spent one-fourth of his birthday money on clothes. He received another $25 a week after. If he has a total of $70 now, how much did he have before he went shopping?
$60
3/2 (4x-10)≤ 2(x+8)+1
x≤ 8
Keith has $500 in a savings account at the beginning of the summer. He wants to have at least $200 in the account by the end of the summer (no income). He withdraws $25 each week for food, clothes, and movie tickets.
The number of weeks that Keith can withdraw money from his account is 12 weeks or less.
How to check your solution?
You plugging back your solution to Original equation.