Answer:
study :)
Step-by-step explanation:
1.2+d+0.4=9.7
1.6+d=9.7
-1.6. -1.6
D=8.1
Answer:
- -20 = 20
Step-by-step explanation:
The "opposite" here means we take the negative of -20 C.
So we can write - -20 which is equal to 20.
So the first option is correct, - -20 = 20.
Answer:
(0,-3)
Step-by-step explanation:
2x-y = 3
x+2y = -6
Multiply the first equation by 2 so we can eliminate y
2(2x-y =3)
4x -2y = 6
Add this to the second equation
4x -2y = 6
x+2y = -6
-----------------
5x +0y = 0
x = 0
Now find t
x+2y = -6
0+2y = -6
2y =-6
Divide by 2
y = -3
Answer:
Step-by-step explanation:
the solution is right
x^2-6x-7=0:
x^2-6x-7=0
(add 7 to both sides)
x^2-6x=7
x^2-6x+9=7+9 (the coefficient of x² will be used to divide all sides)for here its 1, it will remain same ,
then we get the coefficient of x, divide it by 2 and square it and add it to both sides
which is like these
x²-6x=7
the coefficient of x is -6
-6/2 = -3, square it (-3)² = 9
then add 9 to both sides
x^2-6x+9=7+9
simplifiy the squares on the left hand side
x²+9 = (x-3)²
(x-3)^2=16
√(x-3)^2 )=±√16
x-3=± 4
x=-3±4
then simplify each sign
x=-3+4 x=-3-4
x=1 x=-7
