Question

What is the solution to 12x+18=4(5x-3) A. 1 1/2 B. 3 3/4 C. 7/8 D. 4/15

Answer 1

`B. \:3(3)/(4)`

Explanation:

`12x+18=4(5x-3)\\\\\mathrm{Expand\:}4\left(5x-3\right):\quad 20x-12\\12x+18=20x-12\\\\\mathrm{Subtract\:}18\mathrm{\:from\:both\:sides}\\12x+18-18=20x-12-18\\\\Simplify\\12x=20x-30\\\\\mathrm{Subtract\:}20x\mathrm{\:from\:both\:sides}\\12x-20x=20x-30-20x\\\\Simplify\\-8x=-30\\\\\mathrm{Divide\:both\:sides\:by\:}-8\\(-8x)/(-8)=(-30)/(-8)\\\\Simplify\\x=(15)/(4)\\\\15/ 4 = 3remainder3\\\\=3(3)/(4)`

Answer 2

B

Explanation:

So we have the equation:

`12x+18=4(5x-3)`

Distribute the right:

`12x+18=20x-12`

Add 12 to both sides:

`12x+30=20x`

Subtract 12 from both sides:

`30=8x`

Divide both sides by 8:

`x=30/8`

Reduce:

`x=15/4`

Put into mixed fractions:

`x=12/4+3/4=3\text{ } 3/4`

Our answer is B :)