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# C1 help! watch

1. Hi, got this question wrong but dont know what i did wrong. Please can you show me how its done? Thanks.

Solve simultaneous equations:
x+y=11
xy=30

PS i got x=17, y=-6 or x=16, y=-5
2. (Original post by YsfAli)
Hi, got this question wrong but dont know what i did wrong. Please can you show me how its done? Thanks.

Solve simultaneous equations:
x+y=11
xy=30

PS i got x=17, y=-6 or x=16, y=-5
Make x or y the subject of either equation, then substitute the result into the other one.

Your solution only solves the first equation. Remember that both equations need to be satisfied simultaneously!
3. (Original post by YsfAli)
Hi, got this question wrong but dont know what i did wrong. Please can you show me how its done? Thanks.

Solve simultaneous equations:
x+y=11
xy=30

PS i got x=17, y=-6 or x=16, y=-5
Post your working and we can tell you where you've gone wrong.
4. (Original post by YsfAli)
Hi, got this question wrong but dont know what i did wrong. Please can you show me how its done? Thanks.

Solve simultaneous equations:
x+y=11
xy=30

PS i got x=17, y=-6 or x=16, y=-5
Truthfully, this is a ridiculously easy question that you can see the answer to without solving normally - just think about factors of 30.

But for the actual method, just rearrange the first equation and substitute the result into the second.

You'll find it makes a nice easy quadratic
5. It's 5 and 6

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