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32 votes
32 votes
Solve for w.
2w²-7w=4

User Guscht
by
2.5k points

1 Answer

18 votes
18 votes

Answer:

w = 4

w = -1/2

Explanation:

so first of all this looks like a quadratic equation . I say this because you can subtract 4 to get 0 on one side . so you will have 2w²-2w-4=0.

to solve quadratic equations you need to use the quadratic formula . keep in mind you can only use the quadratic formula when your own quadratic equation is set set equal to 0. quadratic formula is equal to:

x= (-b±sqrt(b²-4ac))÷2a

now because this is a quadratic you can identify the values x, b, a, and c. we know that if it is a quadratic equation then the equation will be ax²+ BX + C. this is the basic formula for a quadratic equation so your values will be a equals 2 and B = -7 and C equals -4 and W equals X .

now because we know these values we can substitute it into the quadratic formula that i mentioned earlier .

x=(-(-7) ± sqrt( (-7)²-(4×2×(-4)) ) ) ÷ (2×2)

when you're simplify this you get

x= (7±sqrt(49+32))÷4

x= 7±sqrt(81) ÷ 4

x= (7±9)÷4

for quadratics it's normal that the x value is going to be two different values so don't panic at that !

the first x value

x= (7+9)÷4

= 16÷4

=4

the second x value

x= (7-9)÷4

=(-2)÷4

=-1/2

now remember that we said W equals X so the value of w will be 4 or -1/2 .

User Kerriann
by
2.9k points
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