Finding possible solutions....?

Question

1. x^2 - 18 = 7x

2. 5^x^2-2x-15 = 1

3. sqrt(3x + 18) = x

4. (x - 2)(x + 3) = 6

5. log sub 2(x + 1) = 3

Thanks..

Answer 1

1. Subtract 7x and factor:

x^2-7x-18=(x-9)(x+2) x=9, -2

2. Gonna assume that's 5x^2-2x-15=1

Subtract 1

5x^2-2x-16

Quadratic formula:

(2+-sqrt(4+4*5*16))/10

(2+-sqrt(324))/12

sqrt(324)=18

(2+-18)/12

x=-4/3, 5/3

3. Square both sides

3x+18=x^2

x^2-3x-18=0

(x-6)(x+3)=0

x=6, -3

4. FOIL Method:

x^2+x-6=6

x^2+x-12=0

(x-3)(x+4)=0

x=3, -4

5. Rewrite in exponential form:

x+1=2^3

x+1=8

x=7