8p² - 16p = 10
8p² - 16p - 10 = 0 Divide through by 2
4p² - 8p - 5 = 0
Multiply first and last coefficients: 4*-5 = -20
We look for two numbers that multiply to give -20, and add to give -8
Those two numbers are 2 and -10.
Check: 2*-10 = -20 2 + -10 = -8
We replace the middle term of -8p in the quadratic expression with 2p -10p
4p² - 8p - 5 = 0
4p² + 2p - 10p - 5 = 0
2p(2p + 1) - 5(2p + 1) = 0
(2p + 1)(2p - 5) = 0
2p + 1 = 0 or 2p + 5 = 0
2p = 0 -1 2p = 0 - 5
2p = -1 2p = -5
p = -1/2 p = -5/2
The solutions are p = -1/2 or -5/2
So to solve for y, we need to get y alone on one side of the equation. So we are going to subtract 9x from both sides of the equation to get:
And since y is negative, we are going to divide both sides by -1 in order to make the y positive:
Answer:
68cm^2
Step-by-step explanation:
Well there's not much to explain - the problem statement does it for us.
The surface area is equal to the sum of areas of the walls. There's 2 l*w walls, 2 l*h walls and 2 h*w walls.
SA = 2*l*h + 2*l*w + 2*h*w
SA = 2*4cm*6cm + 2*4cm*1cm + 2*6cm*1cm = 48cm^2 + 8cm^2 + 12cm^2 = 68cm^2
