7(3x+4)=8(2x-15)+13
2007-02-07 04:22:24 · 3 answers · asked by Michelle P 1 in Science & Mathematics ➔ Mathematics
Distribute the numbers outside the parenthesis:
7*3x + 7*4 = 8*2x - 8*15 + 13
Multiply out:
21x + 28 = 16x - 120 + 13
Add common terms:
21x + 28 = 16x - 107
Move x's to one side, numbers to the other:
21x - 16x = -107 - 28
Add common terms:
5x = -135
Divide by 5:
x = -27
2007-02-07 04:30:18 · answer #1 · answered by vaca loca 3 · 0⤊ 0⤋
on multiplying the LHS bracket by 7 it becomes 21x+28 and on opening the RHS bracket it becomes 16x-12+13
so the equation will look like 21x+28=16x-120+13
21x+28=16x-107
Now transpose 16x to the LHS and 28 To RHS
So
21x-16x=107-28
5x=79
x=79/5
x=15.8
2007-02-07 04:33:04 · answer #2 · answered by Anonymous 2 · 0⤊ 0⤋
7(3x+4)=8(2x-15)+13
distribute
21x+28=16x-120+13
21x+28=16x-107
subtract 16x from both sides
21x-16x+28=-107+16x-16x
5x+28=-107
subtract 28 from both sides
5x+28-28=-107-28
5x=-135
divide both sides by 5
5x/5=-135/5
x=-27
2007-02-07 04:32:38 · answer #3 · answered by Bill F 6 · 0⤊ 0⤋