Question

Solve

a- 7-2 = 4x-5

b- Simplify
3x(x+6)-3x(6-3x) ​

Answer 1

x=5/4 + 5b/4

b= -1+ 4x/5

The other one is 12x^2

Explanation:

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Answer 2

1) x=-0.5 and x=-3.41

2) 12x^2

Explanation:

a) 7-x^2=4x-5

7-x^2-4x+5=0

-x^2-4x-2=0

Multiply by -1

x^2+4x+2=0

Solve using quadratic formula
`$x=(-b\pm√(b^2-4ac))/(2a)$`

we have a=1, b=4, c=2

Putting values to find x

`x=(-b\pm√(b^2-4ac))/(2a)\\x=(-(4)\pm√((4)^2-4(1)(2)))/(2(1))\\x=(-4\pm√(16-8))/(2)\\x=(-4\pm√(8))/(2)\\x=(-4+√(8))/(2) \ and \ x=(-4-√(8))/(2)\\x=-0.5 \ and \ x=-3.41`

So, x=-0.5 and x=-3.41

b) Simplify

`3x(x+6)-3x(6-3x)`

`3x(x+6)-3x(6-3x)\\=3x^2+18x-18x+9x^2\\=3x^2+9x^2\\=12x^2`