`y = 2x-3`
`y = 4x + 1`
Which value of `x` satisfies both of these equations?
- `x = -2`
- `x = -1`
- `x = 1`
- `x = 2`
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`y = 2x-3`
`y = 4x + 1`
Which value of `x` satisfies both of these equations?
`A`
`text(If)\ x = −2,`
`2(-2)-3` | `= -7` |
`4(-2) + 1` | `= -7` |
`:. x = -2\ \ text(satisfies both.)`
`=>A`
The daily energy requirement, `E` (kilojoules), for a person of mass `m` (kilograms) is calculated using the rule `E = 7m + 7300`.
For Elijah, `E = 7755`.
What is Elijah's mass? (2 marks)
`65\ text{kgs}`
`7755` | `= 7m + 7300` |
`7 m` | `= 455` |
`m` | `= 455/7` |
`= 65\ text(kilograms)` |
`2(3p-5)-3=17`
Solve for `p`. (2 marks)
`p=5`
`2(3p-5)-3` | `=17` | |
`6p-10-3` | `=17` | |
`6p-13` | `=17` | |
`6p` | `=30` | |
`:.p` | `=5` |
`17y+3(5-3y)-5=26`
What value of `y` makes this equation true? (2 marks)
`y=2`
`17y+3(5-3y)-5` | `=26` | |
`17y+15-9y-5` | `=26` | |
`8y+10` | `=26` | |
`8y` | `=16` | |
`:.y` | `=2` |
`6(3a+4)-12=8a-18`
What value of `a` makes this equation true? (2 marks)
`a=-3`
`6(3a+4)-12` | `=8a-18` | |
`18a+24-12` | `=8a-18` | |
`10a` | `=-12-18` | |
`10a` | `=-30` | |
`:.a` | `=-3` |
`2 (4x-2) + 1 +` |
?
|
`= 9x-3` |
What term makes this equation true for all values of `x`? (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
?
|
`= x` |
`2(4x-2) + 1 +` |
?
|
`= 9x-3` |
`8x-4 + 1 +` |
?
|
`= 9x-3` |
`8x-3 +` |
?
|
`= 9x-3` |
?
|
`= x` |
Make `p` the subject of the equation `c = 5/3p + 15`. (2 marks)
`p = 3/5 c-9`
`c` | `= 5/3p + 15` |
`5/3p` | `= c-15` |
`p` | `= 3/5 (c-15)` |
`= 3/5 c-9` |
Given the formula `C = (A(y + 1))/24`, calculate the value of `y` when `C = 120` and `A = 500`. (3 marks)
--- 6 WORK AREA LINES (style=lined) ---
`4.76`
`text(Make)\ \ y\ \ text(the subject:)`
`C` | `= (A(y + 1))/24` |
`24C` | `= A(y + 1)` |
`y + 1` | `= (24C)/A` |
`y` | `= (24C)/A-1` |
`= (24 xx 120)/500-1` | |
`= 4.76` |
Which of the following correctly expresses `x` as the subject of `y=(ax-b)/(2)` ?
`A`
`y` | `=(ax-b)/(2)` | |
`2y` | `=ax-b` | |
`ax` | `=2y+b` | |
`:.x` | `=(2y+b)/a` |
`=>A`
Which of the following correctly expresses `y` as the subject of the formula `3x-4y-1 = 0`?
`C`
`3x-4y-1` | `= 0` |
`4y` | `= 3x-1` |
`:. y` | `= (3x-1)/4` |
`=> C`
Which of the following correctly expresses `Q` as the subject of `e = iR + Q/C`?
`=> B`
`e` | `= iR + Q/C` |
`Q/C` | `= e-iR` |
`:. Q` | `= C(e-iR)` |
`= Ce-CiR` |
`=> B`
The formula `C = 5/9 (F-32)` is used to convert temperatures between degrees Fahrenheit `(F)` and degrees Celsius `(C)`.
Convert 3°C to the equivalent temperature in Fahrenheit. (2 marks)
--- 5 WORK AREA LINES (style=lined) ---
`37.4\ text(degrees)\ F`
`C` | `= 5/9(F-32)` |
`F-32` | `= 9/5C` |
`F` | `= 9/5C + 32` |
`text(When)\ \ C = 3,`
`F` | `= (9/5 xx 3) + 32` |
`= 37.4\ text(degrees)\ F` |
What is the value of `(a-b)/4`, if `a = 240` and `b = 56`?
`B`
`(a-b)/4` | `= (240-56)/4` |
`= 46` |
`=> B`
The distance in kilometres (`D`) of an observer from the centre of a thunderstorm can be estimated by counting the number of seconds (`t`) between seeing the lightning and first hearing the thunder.
Use the formula `D = t/3` to estimate the number of seconds between seeing the lightning and hearing the thunder if the storm is 1.2 km away. (1 mark)
--- 2 WORK AREA LINES (style=lined) ---
`3.6\ text(seconds)`
`D = t/3`
`text(When)\ \ D = 1.2,`
`t/3` | `= 1.2` |
`t` | `= 3.6\ text(seconds)` |
Which of the following correctly expresses `T` as the subject of `B = 2pi (R + T/2)`?
`A`
`B` | `= 2pi (R + T/2)` |
`B/(2pi)` | `= R + T/2` |
`T/2` | `= B/(2pi)-R` |
`T` | `= B/pi-2R` |
`=> A`
Fred tried to solve this equation and made a mistake in Line 2.
\begin{array}{rl}
4(y+2)-3(y+1)= -3\ & \ \ \ \text{Line 1} \\
4y+8-3y+3= -3\ &\ \ \ \text{Line 2} \\
y+11 =-3\ &\ \ \ \text{Line 3} \\
y =-14& \ \ \ \text{Line 3}
\end{array}
Copy the equation in Line 1.
--- 1 WORK AREA LINES (style=lined) ---
--- 2 WORK AREA LINES (style=lined) ---
`y=-8`
i. | `4(y+2)-3(y+1)` | `=-3\ \ \ \ \ \ \ text(Line)\ 1` |
`4y+8-3y-3` | `=-3\ \ \ \ \ \ text(Line)\ 2` |
ii. | `y+5` | `=-3\ \ \ \ \ \ \ text(Line)\ 3` |
`y` | `=-8\ \ \ \ \ \ \ text(Line)\ 4` |
Which of the following correctly express `x` as the subject of `a=(nx)/5` ?
`B`
`a` | `=(nx)/5` |
`nx` | `=5a` |
`x` | `=(5a)/n` |
`=> B`
Which equation correctly shows `r` as the subject of `S=800(1-r)`?
`A`
`S` | `=800(1-r)` |
`1-r` | `=S/800` |
`r` | `=1-S/800` |
`=(800-S)/800` |
`=>\ A`