2814359
Description
Mind Map by elisfbailey, updated more than 1 year ago
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Created by elisfbailey
over 9 years ago
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Solving Quadratics
- s2+2s-80
- We now factorise
- The 2 numbers in the bracket will be positive and negative
- If the number term in the equation is positive, both the brackets will be positive
- If it is negative, one bracket will be positive and one negative
- If it is negative, one bracket will be positive and one negative
- We can start writing our answer...
- (s )(s )
- We know s will be at the start of both brackets as it is the squared term
- We then need to work out which numbers are in the bracket
- Find two numbers that times to make the number term(-80)
- 10&8, 2&40, 5&16...
- Find a pair of those numbers that also add to make the x term(2s)
- 10 and -8 work!
- Now put these into your brackets...
- (s+10)(s-8)
- To solve this, we have to say that it equals 0
- (s+10)(s-8)=0
- Take the (s+10) bracket
- If (s+10)=0, then s=0-10..
- And 0-10=-10
- And the other part of the brackets...
- (s-8)=0
- becomes...
- s=0+8=8
- You just reverse the signs of the number terms in the bracket!
- So our solutions are...
- s=-10 OR s=8
- We have to write OR not AND as the solution can't be both at the same time
- If in doubt, just write your solutions and nothing else
- s=-10 s=8
- s=-10 s=8
- If in doubt, just write your solutions and nothing else
- We have to write OR not AND as the solution can't be both at the same time
- s=-10 OR s=8
- So our solutions are...
- You just reverse the signs of the number terms in the bracket!
- s=0+8=8
- becomes...
- (s-8)=0
- And the other part of the brackets...
- And 0-10=-10
- If (s+10)=0, then s=0-10..
- Take the (s+10) bracket
- (s+10)(s-8)=0
- To solve this, we have to say that it equals 0
- (s+10)(s-8)
- Now put these into your brackets...
- 10 and -8 work!
- Remember that one number in these pairs will be negative
- Find a pair of those numbers that also add to make the x term(2s)
- 10&8, 2&40, 5&16...
- Find two numbers that times to make the number term(-80)
- We know s will be at the start of both brackets as it is the squared term
- (s )(s )
- If the number term in the equation is positive, both the brackets will be positive
- The 2 numbers in the bracket will be positive and negative
- We now factorise
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