The third choice, 4x²+18x+0.25=0, is correct.
The frame will have the same thickness on both sides of the mirror. Therefore we add 5+x+x to get the total length, and we have 4+x+x to get the total width.
The area is found by multiplying the total width and total length:
A=(5+x+x)(4+x+x)
A=(5+2x)(4+2x)
Multiplying the binomials, we have:
A=5*4+5*2x+2x*4+2x*2x
A=20+10x+8x+4x²
A=20+18x+4x²
We know that the area is 19.75:
19.75=20+18x+4x²
We need quadratics set equal to 0, so subtract 19.75 from each side:
19.75-19.75 = 20+18x+4x²-19.75
0=0.25+18x+4x²
In standard form, it will be:
4x²+18x+0.25=0
Answer:
I don't know about this thing
138 x ? = 75
? = 75/138 = 0.544(3sf)
so about 54.35% (2dp) decrease
Answer:
0.611 = 61.1%
Step-by-step explanation:
'Percent (%)' means 'out of one hundred':
p% = p 'out of one hundred',
p% = p/100 = p ÷ 100.
Note:
100/100 = 100 ÷ 100 = 100% = 1
Multiply a number by the fraction 100/100,
... and its value doesn't change.
Calculate the percent value:
0.611 =
0.611 × 100/100 =
(0.611 × 100)/100 =
61.1/100 =
61.1%;
In other words:
1) Multiply that number by 100.
2) Add the percent sign % to it.
Answer:
The equation in the slope-intercept form is y = 
+ -6 ⇒ C
Step-by-step explanation:
The slope-intercept form of the linear equation is
y = m x + b, where
- m is the slope of the line
∵ The equation is 13x - 3y = 18
→ At first move x from the left side to the right side by subtracting 13x
from both sides
∴ 13x - 13x - 3y = 18 - 13x
∴ - 3y = 18 - 13x
→ Make the coefficient of y equal 1 by dividing both sides by -3
∵ 
∴ y = -6 - (
)
→ Remember (-)(-) = (+)
∴ y = -6 +
→ Switch the two terms of the right side
∴ y = + - 6
∴ The equation in the slope-intercept form is y = + -6
