Simple Equations
Solve: x + 4 =13
x=9
5(y-3) = 35
y = 10
In geometry, an exterior angle of a triangle is equal to the sum of the two opposite interior angles: d = a + b Rearrange this formula to solve for a.
d - b = a OR a = d - b
Sandra found x = -6 when solving the following equation 3x + 14 = -4. Is Sandra correct?
Yes...the left side equals the right side
LS = 3(-6)+14 = -18 + 14 = -4
RS = -4
For the equation 2x - 5 = 31, a student determined that x = 13. Is the student correct?
NO...the left side does not equal the right side.
LS = 2(13)-5=21
RS = 31
Solve: n/4 = -3
n = -12
The area of a rectangle is calculated using the formula: A = L x W. Rearrange the formula to solve for L.
A/W = L OR L = A/W
Rufio solved the equation 3h + 2h - 7 = 4h - 13 and got an answer of h = 6. Is Rufio correct?
NO... the left side does not equal the right side
LS = 3(6) + 2(6) - 7 = 18+12-7 = 23
RS = 4(6) -13 = 11
3(y-5)-2(y-4)= -14
y = -7
The equation of a line is given by y=mx+b. Rearrange the formula to solve for m.
m=(y-b)/x
Estaban found y = 4 when solving the equation
3(2x+5)=39. Is Estaban correct?
Yes... LS=RS
LS = 3(2(4)+5) = 3(8+5) = 3(13) =39
RS = 39
4w + 8 - 5w - 5 = w - 1
w = 2
10c - 6 = -16
c = -1
4(k - 1)/5 = -8
k = -9
The formula P = 2L + 2W represents the perimeter of a rectangle. If the perimeter is 32 cm and the length is 12 cm, then determine the width. Include the units!
W=4cm
Brittany solve the equation 2n+18 = 16 - 4n -28 and calculated n = -5. Is she correct?
Yes she is correct!
Rearrange the formula A = bh/2 to isolate the height, h.
h=2A/b
Solve: 6r + 3 = 33
r = 5
(x - 1)/5 = (x+2)/2
x = -4
When solving the formula A = P(1+rt) to isolate the variable, t, the first step is to use the distributive property to multiply P into the bracket. What would be the next TWO steps to solve for t?
1) subtract P then 2) divide by Pr
When rearranging the equation 9x - 3y = 15 to solve for the variable y, Lucas says y = -3x + 5 and Devin says y = 3x - 5. Who is correct?
Devin is correct.
9x - 3y = 15
-3y = -9x + 15 then divide everything by -3
y = 3x - 5
3(2 - a)/8 = 6
a = -14