Step-by-step explanation:
(3x+20)² is the same as
(3x+20)(3x+20)
you need to have for different numbers
SO
3x*3x is 9x²
3x*20 is 60x
20*3x is also 60x
20*20 is 400
put it together
9x²+60x+60x+400
simplify to
9x²+120x+400
Answer:
Krista put 0.40 in the first equation meant for the number of stamps.
Step-by-step explanation:
Krista's equation
0.40x+y=45
x+0.55y=18.75
The system of Equation should have been
x + y = 45 (1)
0.40x + 0.55y = 18.75 (2)
From (1)
x=45-y
Substitute x=45-y into (2)
0.40(45 - y) + 0.55y = 18.75
18 - 0.40y + 0.55y = 18.75
Collect like terms and you now have
0.55y - 0.40y = 18.75 - 18
0.15y = 0.75
Divide both sides of the equation by 0.15
y = 5
Substitute y=5 into (1)
x + y = 45
x+5=45
x=45-5
x=40
This shows that the stamps that cost 0.40 cents were 40 while those that cost 0.55 cents were 5 in number.
Krista's error:
Krista put 0.40 in the first equation meant for the number of stamps.
Hey there! :)
Answer:
C. (0, -6).
Step-by-step explanation:
In slope-intercept form ( y = mx + b), the 'b' value represents the y-intercept.
In this instance:
y = 4x - 6
The 'b' value is equal to -6. This means that the y-intercept is at (0, -6).
-------------------------------------------------------------------------------------------
The y-intercept can also be solved for by substituting in 0 for x:
y = 4(0) - 6
y = 0 - 6
y = -6.
9.3 × 107 would be the scientific notation
20:200
?:700
200×3.5=700
20×3.5=?
?=70
He can use 70 liters of gasoline on a trip of 700km