You can start by subtracting different equations from each other.
3x + 2y + 3z = 1
subtract
3x + 2y + z = 7
2z = -6
divide by 2
z = -3
add the following two expressions together:
3x + 2y + z = 7
3x + 2y + 3z =1
6x + 4y + 4z = 8
subtract the following two expressions:
6x + 4y + 4z = 8
5x + 5y + 4z = 3
x - y = 5
^multiply the whole equation above by 3
3x - 3y = 15
subtract the following two expressions:
3x - 3y = 15
3x + 2y = 10
-5y = 5
divide each side by -5
y=-1
take the following expression from earlier:
x - y = 5
substitute y value into above equation
x - - 1 = 5
2 negatives make a positive
x + 1 = 5
subtract 1 from each side
x = 4
Therefore x = 4, y = -1, z = -3
I checked these with all 3 equations and they worked :)
(it's quite complicated, comment if you don't understand anything) :)
Hi!
Let's find out how much he has to pay for each of the deals.
Deal 1
£1.75 per mile.
192 x 1.75 = 336
£336
Deal 2
15% off of £680

680 x 15 = 10200
10200/100 = 102
680 - 102 = 578
£578
Deal 3
£90 per day - 1/10
90 x 7 = 630
1/10 of 630 = 63
630 - 63 = 567
£567
The cheapest deal would be Deal 1
Hope this helps! :)
-Peredhel
Answer:
C
Step-by-step explanation:
In this technique, if we have to factorise an expression like ax2+bx+c, we need to think of 2 numbers such that:
N1⋅N2=a⋅c=1⋅−12=−12
AND
N1+N2=b=−1
After trying out a few numbers we get N1=3 and N2=−4
3⋅−4=−12, and 3+(−4)=−1
x2−x−12=x2−4x+3x−12
x(x−4)+3(x−4)=0
(x+3)(x−4)=0
Now we equate the factors to zero.
x+3=0,x=−3
x−4=0,x=4
Answer:
Therefore the least common denominator is 24.
Step-by-step explanation:
2/6 = 8/24
7/8 = 21/24
No more explanation.