I love your video. It made my life easier when I deal with Quadratic + Simultaneous Equation. My teacher taught it for three whole lesson but I don’t understand how to solve it but after watching your video, I found out that it just simple steps like that. Thank you very much and hope there will be more videos like this.
You know i didnt understand simultaneous for 2 years and i failed most exams because of it but yourvideo made me understand wighin 10 mins i am fore be er gratefull cuz i have an exam in 2 hours god blessbyour loveely soul
1:40 for those who are confused with how we got -14x ⁉️ I got confused at first too by doing -7 squared but that’s wrong To solve (x-7)^2 you should do the FOIL technique then you’ll get the answer she got
She expanded the bracket of (x-7)². Do not fall into the trap if writing x²+49, that's not correct. If it helps, write it as separate brackets as (x-7)(x-7): you can then expand them with FOIL to go x²-7x-7x+49 (be careful: timesing 2 negative numbers gives you a positive answer) and you can clean up the middle and that gives you x²-14x+49
Okay listen i need an answer for this today!!’ Why did she divide the whole thing by 2??? I never heard of this method before. Is it alternative to something else??? Please answer today🙏🏽
@@Joen133 I know its not the same day, but if it is still useful, dividing the whole thing by 2 just makes it easier to solve the quadratic, and because the equation is equal to 0, you can multiply or divide by anything as 0 multiplied or divided by anything is still 0 😃
Hey, I really like your videos. Is there maybe a chance that you can help me with this linear and quadratic simultaneous equation. X - 5y = -13 and x(squared) + y (squared) = 13. Thank you
It comes from expanding the (x-7)² which is really (x-7)(x-7) don't fall into the trap of writing x²+49; you have to expand it properly. If you expand out the terms you get x²-7x-7x+49 and you can simplify it to get x²-14x+49
I'll try to clear it up: the bracket is (x-7)² and it's an easy mistake to then go x²-49 or x²+49 but you need to expand it with FOIL like usual: you can rewrite it as (x-7)(x-7) if that helps you: and then expand like normal by doing each term in the first bracket and each in the second: that'll give you x²-7x-7x+49 (the 49 is positive because squaring a negative number gives you a positive answer because multiplying 2 negative numbers gives you a positive answer). You can then clean up x²-7x-7x+49 to give you x²-14x+49
If there's a common factor you can divide everything. It's optional, if you don't you'll still get the right answer, but dividing everything just makes factorising a bit easier
If your second equation is x²+x-3 then it would be like this… Rearrange the first equation to make y the subject y=4-2x. Then you can put the equations equal to each other. Since y equals y, 4-2x=x²+x-3. Then, x²+3x-7=0. You can use the quadratic formula from here to solve and find x
When you expand (x-7)², you're really doing (x-7)(x-7) and if you expand that like normal, you get x²-7x-7x+49 which you can simply to get x²-14x+49, that's why it's not just x²+49, which is a very common, and understandable, mistake
The (x-7)² is just a shorter way to write (x-7)(x-7) and you then expand that with FOIL like normal: that gives you x²-7x-7x+49 which simplifies down to x²-14x+49
That's what -7 squared is because it's -7×-7 and timesing 2 negative numbers gives you a positive number. If you're using a calculator, be careful: always type in (-7)² if you need to square a negative number. If you just type in -7² it interprets it as -(7×7) and will say -49
Everything divided nicely by 2, so you can divide everything through like that if it makes the numbers easier. You don't have to, you'll still get the right answer if you don't, but it just makes it easier to factorise
It's because (x-7)² is NOT x²-49 (try with x as a number, it will not work) you need to expand properly as (x-7)(x-7) where you use FOIL or however you expand brackets and then you get x²-14x+49
You have to be careful when you square brackets: (x-7)² is not x²-49 because you're really doing (x-7)(x-7) which you have to expand out properly with foil and it gives you x²-14x+49
When you expand (x-7)² you're actually doing (x-7)(x-7) which expanded with foil is x²-7x-7x+49 and you can combine the middle terms and get x²-14x+49: that's why it's not just x²+49
You can make y the subject of the first one by doing -2x to each side and you get y=5-2x Substitute into the 2nd equation: x²+(5-2x)²=3 Expand the brackets x²+(5-2x)(5-2x) x²+25-10x-10x+4x² x²+4x²-20x+25 5x²-20x+25=3 5x²-20x+22=0 this one doesn't factorise nicely so you have to use the quadratic formula or complete the square (which I'm going to do) Factorise out 5: 5(x²-4x+4.4) Halve the number before the x, put that in the brackets, square what you get after that, and add the number at the end: 5[(x-2)²+4-4.4] 5[(x-2)²-0.4] 5(x-2)²-2=0 5(x-2)²=2 (x-2)²=2/5 square root each side x-2=±√2/√5 Rationalise the denominator x-2=±√10/5 x=2±√10/5 That was a pretty horrid answer and you could put it back into the original equation to find y in each case
@@shalifamotaung9110 what happened was that there was (x-7)² but you can write that out as (x-7)(x-7) and then expand it with FOIL to get x²-7x-7x+49 (the 49 is positive because you're multiplying 2 negative numbers and that gives you a positive answer). That simplifies down to x²-14x+49
So when it's a whole bracket squared it's the same as (x-7)(x-7), which you can expand out in the usual way but be careful: it's not x²+49. When you expand you get x²-7x-7x+49 and you can then simplify the middle down to -14x
