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1.1 Solve for x: 1.1.1 $x^2 + 5x - 6 = 0$ 1.1.2 $4x^2 + 3x - 5 = 0$ (correct to TWO decimal places) 1.1.3 $4x^2 - 1 < 0$ 1.1.4 $\left( \sqrt{32+x} \right) \left( \sqrt{32-x} \right) = x$ 1.2 Solve simultaneously for x and y: $y + x = 12$ and $xy = 14 - 3x$ 1.3 Consider the product $1 \times 2 \times 3 \times 4 \times 30$ - NSC Mathematics - Question 1 - 2019 - Paper 1

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1.1-Solve-for-x:--1.1.1-$x^2-+-5x---6-=-0$----1.1.2-$4x^2-+-3x---5-=-0$-(correct-to-TWO-decimal-places)----1.1.3-$4x^2---1-<-0$----1.1.4-$\left(-\sqrt{32+x}-\right)-\left(-\sqrt{32-x}-\right)-=-x$----1.2-Solve-simultaneously-for-x-and-y:---$y-+-x-=-12$---and--$xy-=-14---3x$----1.3-Consider-the-product-$1-\times-2-\times-3-\times-4-\times-30$-NSC Mathematics-Question 1-2019-Paper 1.png

1.1 Solve for x: 1.1.1 $x^2 + 5x - 6 = 0$ 1.1.2 $4x^2 + 3x - 5 = 0$ (correct to TWO decimal places) 1.1.3 $4x^2 - 1 < 0$ 1.1.4 $\left( \sqrt{32+x} \right) ... show full transcript

Worked Solution & Example Answer:1.1 Solve for x: 1.1.1 $x^2 + 5x - 6 = 0$ 1.1.2 $4x^2 + 3x - 5 = 0$ (correct to TWO decimal places) 1.1.3 $4x^2 - 1 < 0$ 1.1.4 $\left( \sqrt{32+x} \right) \left( \sqrt{32-x} \right) = x$ 1.2 Solve simultaneously for x and y: $y + x = 12$ and $xy = 14 - 3x$ 1.3 Consider the product $1 \times 2 \times 3 \times 4 \times 30$ - NSC Mathematics - Question 1 - 2019 - Paper 1

Step 1

1.1.1 $x^2 + 5x - 6 = 0$

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Answer

To solve the quadratic equation, we can factor it as follows:

(x+6)(x1)=0(x + 6)(x - 1) = 0

Setting each factor to zero gives:

  1. x+6=0x=6x + 6 = 0 \Rightarrow x = -6
  2. x1=0x=1x - 1 = 0 \Rightarrow x = 1

Thus, the solutions are x=6x = -6 or x=1x = 1.

Step 2

1.1.2 $4x^2 + 3x - 5 = 0$ (correct to TWO decimal places)

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Answer

Using the quadratic formula:

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

where a=4a = 4, b=3b = 3, and c=5c = -5:

x=3±3244(5)24    x=3±9+808=3±898x = \frac{-3 \pm \sqrt{3^2 - 4 \cdot 4 \cdot (-5)}}{2 \cdot 4} \implies x = \frac{-3 \pm \sqrt{9 + 80}}{8} = \frac{-3 \pm \sqrt{89}}{8}

Calculating the values:

  1. x=3+8980.80x = \frac{-3 + \sqrt{89}}{8} \approx 0.80 (to two decimal places)
  2. x=38981.55x = \frac{-3 - \sqrt{89}}{8} \approx -1.55 (to two decimal places)

Thus, the values are approximately x0.80x \approx 0.80 and x1.55x \approx -1.55.

Step 3

1.1.3 $4x^2 - 1 < 0$

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Answer

To solve the inequality, we first rewrite it as:

4x2<14x^2 < 1

Dividing both sides by 4:

x2<14x^2 < \frac{1}{4}

Taking the square root of both sides gives:

12<x<12-\frac{1}{2} < x < \frac{1}{2}

The solution set is therefore x(12,12)x \in \left(-\frac{1}{2}, \frac{1}{2}\right).

Step 4

1.1.4 $\left( \sqrt{32+x} \right) \left( \sqrt{32-x} \right) = x$

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Answer

First, we can square both sides to eliminate the square roots:

(32+x)(32x)=x    32+x32x=x.\left( \sqrt{32+x} \right) \left( \sqrt{32-x} \right) = x \implies \sqrt{32+x} \cdot \sqrt{32-x} = x.

This simplifies to:

(32+x)(32x)=x    322x2=x2    1024x2=x2.\sqrt{(32+x)(32-x)} = x \implies 32^2 - x^2 = x^2 \implies 1024 - x^2 = x^2.

Rearranging gives:

1024=2x2    x2=512    x=512=16    x=4 (considering only positive solutions). 1024 = 2x^2 \implies x^2 = 512 \implies x = \sqrt{512} = 16 \implies x = 4 \text{ (considering only positive solutions)}.

Step 5

1.2 Solve simultaneously for x and y: $y + x = 12$ and $xy = 14 - 3x$

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Answer

From the first equation, we can express y in terms of x:

y=12x.y = 12 - x.

Substituting this into the second equation:

x(12x)=143x    12xx2=143x    x215x+14=0.x(12 - x) = 14 - 3x \implies 12x - x^2 = 14 - 3x \implies x^2 - 15x + 14 = 0.

Factoring this gives:

(x14)(x1)=0(x - 14)(x - 1) = 0

Thus, x=14x = 14 or x=1x = 1. Now substituting back to find y:

  1. If x=14x = 14, then y=1214=2y = 12 - 14 = -2.
  2. If x=1x = 1, then y=121=11y = 12 - 1 = 11.

The solutions for (x, y) pairs are thus (14,2)(14, -2) and (1,11)(1, 11).

Step 6

1.3 Consider the product $1 \times 2 \times 3 \times 4 \times 30$. Determine the largest value of k such that $3^k$ is a factor of this product.

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Answer

To determine the largest value of k such that 3k3^k divides the product:

  1. Factor each term in the product:

    • 1=11 = 1
    • 2=22 = 2
    • 3=313 = 3^1
    • 4=224 = 2^2
    • 30=23530 = 2 \cdot 3 \cdot 5
  2. Now count the total factors of 3:

    • From 33: 11 factor
    • From 3030: 11 factor

Thus, the total number of factors of 3 in the product is 1+1=21 + 1 = 2. Therefore, k=2k = 2.

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