All Junior Cert Mathematics posts
• #### Quatratic equations so52307

The study clix only showed some of the formulas... But if a long question pops up, i don't get it.

Heres the question, can you solve it for me?

A positive number is squared and three times the number is then added. The result is 88. Find the number.

1. #### aoifehayes

x^2+3x=88

x^2+3x-88

can you take it from here?

2. #### DylanLynch

I find putting it down in words first helps me out. Think about what EXACTLY they're asking. If you have a number and you multiply it by itself (ie; squaring it) and then add on your starting number 3 times you'll get 88.

Next write it down equation-wise (User aoifehayes has it done already).

Now you can use factorising OR the "-b method" to find values for x.

Sub back in your values for x to make sure they work (ie; the left side of the equals sign equals the right side of the equals sign) and voila! Solved.

3. #### Art1998

I use the big X method, its extremely handy once you get used to it. Look it up online.

4. #### Art1998

X2 + 3x=88......... X2+3x-88= 0, now you have a quadratic an should be able to solve it with whatever formula you usually use